Quantitative Aptitude  Average  Formula & Concept Quiz
#  Quiz 

1
Discuss

Formula & Concept
The average age of a class is 15.8 years. The average age of the boys in the class is 16.4 years while that of the girls is 15.4 years. What is the ratio of boys to girls in the class?
Solution 
2
Discuss

Formula & Concept
The average of x number is y and average of y numbers is x. Then the average of all the numbers taken together is
Solution 
3
Discuss

Formula & Concept
Find the average of all prime numbers between 30 and 50.
Solution 
4
Discuss

Formula & Concept
Find the average of the first 40 natural numbers.
Solution 
5
Discuss

Formula & Concept
In Arun's opinion, his weight is greater than 65 kg but less than 72 kg. His brother doest not agree with Arun and he thinks that Arun's weight is greater than 60 kg but less than 70 kg. His mother's view is that his weight cannot be greater than 68 kg. If all are them are correct in their estimation, what is the average of different probable weights of Arun?
Solution 
6
Discuss

Formula & Concept
The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero ?
Solution 
7
Discuss

Formula & Concept
If the mean of a,b,c is M and ab+bc+ca=0, then the mean of a^{2},b^{2},c^{2} is:
Solution 
8
Discuss

Formula & Concept
The average annual income (in Rs.) of certain agricultural workers is S and that of other workers is T. The number of agricultural workers is 11 times that of other workers. Then the average monthly income (in Rs.) of all the workers is
Solution 
9
Discuss

Formula & Concept
A library has an average of 510 visitors on Sundays and 240 on other days. The average number of visitors per day in a month of 30 days beginning with a Sunday is
Solution 
10
Discuss

Formula & Concept
The average of six number is x and the average of three of these is y. the average of the remaining three is z, then
Solution 
11
Discuss

Formula & Concept
Out of 9 persons, 8 persons spent Rs. 30 on each of their meals. The ninth one spends Rs. 20 more than the average expenditure of all the nine. The total money spent by all of them was
Solution 
12
Discuss

Formula & Concept
The average salary of all the workers in a workshop is Rs.8000. The average salary of 7 technicians is Rs.12000 and the average salary of the rest is Rs.6000. The total number of workers in the workshop is
Solution 
13
Discuss

Formula & Concept
Distance between two stations A and B is 778km. A train covers the journey from A to B at 84 km per hour and returns back to A with a uniform speed of 56 km per hour. Find the average speed of train during the whole journey.
Solution 
14
Discuss

Formula & Concept
The average weight of 10 oarsmen in a boat is increased by 1.5kg when one of the crew who weighs 58kg is replaced by a new man.
Solution 
15
Discuss

Formula & Concept
There were 35 students in a hostel. Due to the admission of 7 new student, the expenses of the mess were increased by Rs. 42 per day, while the average expenditure per head diminished by Re 1. What was the original expenditure of the mess?
Solution 
16
Discuss

Formula & Concept
A batsman makes a score of 87 runs in the 17^{th} inning and thus increases his average by 3. Find his average after 17^{th} inning.
Solution 
17
Discuss

Formula & Concept
10 years ago, the average age of a family of 4 members was 24 years. Two children having been born (with age difference of 2 years), the present average age of the family is again 24 years. Then the present age of the youngest child is:
Solution 
18
Discuss

Formula & Concept
A cricketer has a certain average for 9 innings, In the tenth inning he scores 100 runs there by increasing his average by 8 runs. His new average is
Solution 
19
Discuss

Formula & Concept
The reduction in the speed of an engine is directly proportional to the square of the number of bogies attached to it. The speed of the train is 100 km/hr when there are 4 bogies and 55 kmph when there are 5 bogies. What is the maximum number of bogies that can be attached to the train so that it can move?
Solution 
20
Discuss

Formula & Concept
Ajit has a certain average for 9 innings. In the tenth innings, he scores 100 runs thereby increasing his average by 8 runs. His new average is:
Solution 
21
Discuss

Formula & Concept
The average temperature for Wednesday, Thursday and Friday was 40°C. The average for Thursday, Friday and Saturday was 41° C. If temperature on Saturday was 42° C, what was the temperature on Wednesday?
Solution 
22
Discuss

Formula & Concept
The average of the first five multiples of 9 is:
Solution 
23
Discuss

Formula & Concept
The speed of the train going from Nagpur to Allahabad is 100 km/h while when coming back from Allahabad to Nagpur, its speed is 150 km/h. find the average speed during whole journey.
Solution 
24
Discuss

Formula & Concept
Find the average of first 97 natural numbers.
Solution 
25
Discuss

Formula & Concept
The average age of three boys is 15 years. If their ages are in ratio 3 : 5 : 7, the age of the youngest boy is
Solution 
26
Discuss

Formula & Concept
The average of a group of men is increased by 5 years when a person aged of 18 years is replaced by a new person of aged 38 years. How many men are there in the group?
Solution 
27
Discuss

Formula & Concept
In a boat there are 8 men whose average weight is increased by 1 kg when 1 man of 60 kg is replaced by a new man. What is weight of new comer?
Solution 
28
Discuss

Formula & Concept
The average of 25 results is 18. The average of first 12 of those is 14 and the average of last 12 is 17. What is the 13th result?
Solution 
29
Discuss

Formula & Concept
A train covers the first 16 km at a speed of 20 km per hour another 20 km at 40 km per hour and the last 10 km at 15 km per hour. Find the average speed for the entire journey.
Solution 
30
Discuss

Formula & Concept
The average monthly salary of 660 workers in a factory is Rs. 380. The average monthly salary of officers is Rs. 2100 and the average monthly salary of the other workers is Rs. 340. Find the number of other workers.
Solution 
31
Discuss

Formula & Concept
The average marks of four subjects is 120. If 33 was misread as 13 during the calculation, what will be the correct average?
Solution 
32
Discuss

Formula & Concept
Students of three different classes appeared in common examination. Pass average of 10 students of first class was 70%, pass average of 15 students of second class was 60% and pass average of 25 students of third class was 80% then what will be the pass average of all students of three classes?
Solution 
33
Discuss

Formula & Concept
A man travels equal distances of his journey at 40, 30 and 15 km/h. respectively. Find his average speed for whole journey.
Solution 
34
Discuss

Formula & Concept
Five years ago, the average age of A, B, C and D was 45 yr. with E joining them now, the average of all the five is 49 yr. How old is E?
Solution 
35
Discuss

Formula & Concept
Average of 80 numbers are 42. When 5 more numbers are included, the average of 85 numbers become 45. Find the average of 5 numbers.
Solution 
36
Discuss

Formula & Concept
Find the average increase rate, if increase in the population in the first year is 30% and that in the second year is 40%.
Solution 
37
Discuss

Formula & Concept
Onefourth of certain journey is covered at the rate of 25 km/h, onethird at the rate of 30 km/h and the rest at 50 km/h. Find the average speed for the whole journey.
Solution 
38
Discuss

Formula & Concept
A batsman makes a score of 270 runs in the 87th inning and thus increase his average by a certain number of runs that is a whole number. Find the possible values of the new average.
Solution 
39
Discuss

Formula & Concept
There are five boxes in cargo hold. The weight of the first box is 200 kg and the weight of the second box is 20% higher than the weight of the third box, whose weight is 25% higher than the first box's weight. The fourth box at 350 kg is 30% lighter than the fifth box. Find the difference in the average weight of the four heaviest boxes and the four lightest boxes.
Solution 
40
Discuss

Formula & Concept
A school has only four classes that contain 10, 20, 30 and 40 students respectively. The pass percentage of these classes are 20%, 30%, 60% and 100% respectively. Find the pass % of the entire school.
Solution 
41
Discuss

Formula & Concept
19 people went to a hotel for combine dinner party 13 of them spent Rs. 79 each on their dinner and rest spent 4 more than the average expenditure of all the 19. What was the total money spent by them.
Solution 
42
Discuss

Formula & Concept
The average weight of 47 balls is 4 g. if the weight of the bag (in which the balls are kept) be included; the calculated average weight per ball increases by 0.3 g. What is the weight of the bag?
Solution 
43
Discuss

Formula & Concept
A cricketer scored some runs in his 21st innings, as a result, his average runs increased by 3. If the present average run is 40, how many runs he scored in the final innings?
Solution 
44
Discuss

Formula & Concept
Ajay working in a Cellular company as a salesman. His monthly salary is Rs. 200. But he gets bonus as per given rule. If he sells sim cards of Rs. X then his bonus will be . In the first quarter of the year his average sale was Rs. 3000 per month. In the next 5 five month his average sale was Rs. 5000 per month and for next four month his average sale was Rs. 8000 per month. What is the average earning per month for the whole year?
Solution 
45
Discuss

Formula & Concept
A man has 'n' magical eggs whose average weight is 'k' gm. Each of the 'n' eggs produces 'n' eggs next day such that the average weight of 'n' eggs produced is same as that of the parental egg for each 'n' groups individually i.e. each egg produces 'n' eggs of next generation and average weight of all the 'n' eggs of next generation is same as the weight of the mother egg. This process is continued without any change in pattern. What is the total weight of all the eggs of rth generation, where the initial number of eggs with man are considered as the eggs of first generation.
Solution 
46
Discuss

Formula & Concept
A man started his journey from Lucknow to Kolkata, which is 200 km, at the speed of 40 kmph then he went to Banglore which is 300 km, at the speed of 20 kmph. Further he went to Ahmedabad which is 500 km, at the speed of 10 kmph. The average speed of the man is :
Solution 
47
Discuss

Formula & Concept
The average age of A, B, C, D and E is 40 years. The average age of A and B is 35 years and the average of C and D is 42 years. Age of E is :
Solution 
48
Discuss

Formula & Concept
The mean weight of 100 students in a class is 46 kg. The mean weight of boys is 50 and of girls is 40 kg. Therefore, the number of boys is:
Solution 
49
Discuss

Formula & Concept
There are three categories of jobs A, B and C. The average salary of the student who got the job of A and B categories is 26 lakh per annum. The average salary of the students who got the job of B and C category is 44 lakh per annum and the average salary of those students who got the job of A and C categories is 34 lakh per annum. The most appropriate (or closet) range of average salary of all the three categories (if it is known that each student gets only one category of jobs i.e. , A, B and C):
Solution 
50
Discuss

Formula & Concept
A has 50 coins of 10 paise denominations. While B has 10 coins of 50 paise denominations. C has 20 coins of 25 paise denominations while D has 25 coins of 20 paise denominations. The average number of paise per person is :
Solution 
51
Discuss

Formula & Concept
The average income of A, B and C is Rs. 12,000 per month and average income of B, C and D is Rs. 15,000 per month. If the average salary of D be twice that of A, then the average salary of B and C is in Rs. :
Solution 
52
Discuss

Formula & Concept
A passenger travels from Delhi to Merut at a speed of 30 kmph and return with a speed of 60 kmph. What is the average speed?
Solution 
53
Discuss

Formula & Concept
The average of 20 students is 12 years, if the teacher's age is included, average increases by one. The age of the teacher is:
Solution 
54
Discuss

Formula & Concept
The average wages of a worker during a fortnight comprising 15 consecutive working days was Rs. 90 per day. During the first 7 days, his average wages was Rs. 87/day and the average wages during the last 7 days was Rs. 92/day. What was his wage on the 8th day?
Solution 
55
Discuss

Formula & Concept
40% of the employees in a factory are workers. All the remaining employees are executives. The annual income of each worker is Rs. 390. The annual income of each executive is Rs. 420. What is the average annual income of all the employees in the factory together?
Solution 
56
Discuss

Formula & Concept
The average price of 10 books is Rs.12 while the average price of 8 of these books is Rs.11.75. Of the remaining two books, if the price of one book is 60% more than the price of the other, what is the price of each of these two books?
Solution 
57
Discuss

Formula & Concept
In a set of three numbers, the average of first two numbers is 2, the average of the last two numbers is 3, and the average of the first and the last numbers is 4. What is the average of three numbers?
Solution 
58
Discuss

Formula & Concept
Of the three numbers, the first is twice the second and the second is twice the third. The average of the reciprocal of the numbers is 7/72. The numbers are:
Solution 
59
Discuss

Formula & Concept
The average monthly salary of 12 workers and 3 managers in a factory was Rs. 600. When one of the manager whose salary was Rs. 720, was replaced with a new manager, then the average salary of the team went down to 580. What is the salary of the new manager?
Solution 
60
Discuss

Formula & Concept
The average of five different positive numbers is 25. x is the decrease in the average when the smallest number among them is replaced by 0. What can be said about x?
Solution 
61
Discuss

Formula & Concept
In 2011, the arithmetic mean of the annual incomes of Ramesh and Suresh was Rs. 3800. The arithmetic mean of the annual incomes of Suresh and Pratap was Rs. 4800, and the arithmetic mean of the annual incomes of Pratap and Ramesh was Rs. 5800. What is the arithmetic mean of the incomes of the three?
Solution 
62
Discuss

Formula & Concept
In Arun's opinion, his weight is greater than 65 kg but less than 72 kg. His brother does not agree with Arun and he thinks that Arun's weight is greater than 60 kg but less than 70 kg. His mother's view is that his weight cannot be greater than 68 kg. If all are them are correct in their estimation, what is the average of different probable weights of Arun?
Solution 
63
Discuss

Formula & Concept
A student finds the average of 10 positive integers. Each integer contains two digits. By mistake, the boy interchanges the digits of one number say ba for ab. Due to this, the average becomes 1.8 less than the previous one. What was the difference of the two digits a and b?
Solution 
64
Discuss

Formula & Concept
The average of first five multiples of 3 is:
Solution 
65
Discuss

Formula & Concept
There are two sections A and B of a class, consisting of 36 and 44 students' respectively. If the average weight of section A is 40kg and that of section B is 35kg, find the average weight of the whole class.
Solution 
66
Discuss

Formula & Concept
The average of 50 numbers is 30. If two numbers, 35 and 40 are discarded, then the average of the remaining numbers is nearly:
Solution 
67
Discuss

Formula & Concept
The average score of a cricketer for ten matches is 38.9 runs. If the average for the first six matches is 42, then find the average for the last four matches.
Solution 
68
Discuss

Formula & Concept
A batsman makes a score of 87 runs in the 17th inning and thus increases his average by 3. Find his average after 17th inning.
Solution 
69
Discuss

Formula & Concept
There were 35 students in a hostel. Due to the admission of 7 new students the expenses of the mess were increased by Rs.42 per day while the average expenditure per head diminished by Re 1. What was the original expenditure of the mess?
Solution 
70
Discuss

Formula & Concept
Nine persons went to a hotel for taking their meals. Eight of them spent Rs. 12 each on their meals and the ninth spent Rs. 8 more than the average expenditure of all the nine. What was the total money spent by them.
Solution 
71
Discuss

Formula & Concept
David obtained 76, 65, 82, 67 and 85 marks (out of 100) in English, mathematics, physics, chemistry and biology. What are his average marks?
Solution 
72
Discuss

Formula & Concept
The average of runs of a cricket player of 10 innings was 32. How many runes must be made in his next innings so as to increase his average of runs by 4?
Solution 
73
Discuss

Formula & Concept
Mean of 10 numbers is 30. Later on it was observed that numbers 15, 23 are wrongly taken as 51, 32. The correct mean is :
Solution 
74
Discuss

Formula & Concept
The average age of a family of 10 members is 20 years. If the age of the youngest member of the family is 10 years, then the average age of the members of the family just before the birth of the youngest member was approximately.
Solution 
75
Discuss

Formula & Concept
a, b, c, d, e, f, g are consecutive even numbers. j, k, l, m, n are consecutive odd numbers. The average of all the numbers is :
Solution 
76
Discuss

Formula & Concept
Out of four numbers the average of the first three is 16 and that of the last three is 15. If the last number is 20, than first number is :
Solution 
77
Discuss

Formula & Concept
Mukesh has twice as much money as Soham. Soham has 50% more money than Pankaj. If the average money with them is Rs. 110, then Mukesh has :
Solution 
78
Discuss

Formula & Concept
The mean high temperature of the first four days of a week is 25°C whereas the mean of the last four days is 25.5°C. If the mean of the whole week is 25.2°C then the temperature of the 4th day is :
Solution 
79
Discuss

Formula & Concept
If the average of x and 1/x(X\( \ne \)0) is M, then the average of x2 and 1/x^{2} is :
Solution 
80
Discuss

Formula & Concept
The average weight of 3 men, A, B and C is 84 kg. Another man D joins the group and the average now becomes 80 kg. If another man E whose weight is 3 kg more than that of D, replaces A then the average weight of B, C, D and E becomes 79 kg. What is the weight of A ?
Solution 
81
Discuss

Formula & Concept
Average of two numbers is 8 and average of other three numbers is 3; the average of the five numbers is :
Solution 
82
Discuss

Formula & Concept
An elevator can carry maximum of 16 passengers with an average weight of 80 kg. However, four boys more than the maximum carrying capacity of the elevator entered it making the average weight as 86 kg and overloading the elevator. What is the average weight of those four boys ?
Solution 
83
Discuss

Formula & Concept
Average weight of 25 students of a class is 50 kg. If the weight of the class teacher is included , the average is increased by 1 kg. The weight of the teacher is ?
Solution 
84
Discuss

Formula & Concept
The mean of 100 items was 46. Later on it was discovered that an item 16 was misread as 61 and another item 43 was misread as 34. It was also found that the number of item was 90 and not 100. Then what is the correct mean ?
Solution 
85
Discuss

Formula & Concept
The average of four consecutive even numbers is 15. The 2nd highest number is :
Solution 
86
Discuss

Formula & Concept
The average of runs scored by a cricketer in his 99 innings is 99. How many runs will he have to score to his 100th innings so that his average of runs in 100 innings will become 100 ?
Solution 
87
Discuss

Formula & Concept
A team of 8 persons joins in a shooting competition. The best marksman scored 85 points. If he had scored 92 points, the average score for the team would have been 84. The number of points the team scored was :
Solution 
88
Discuss

Formula & Concept
What is the average of the first six (positive) odd number each of which is divisible by 7?
Solution 
89
Discuss

Formula & Concept
A cricketer had a certain average of runs for his 64 innings. In his 65th innings, he is bowled out for no score on his part. This brings down his average by 2 runs. His new average of runs is :
Solution 
90
Discuss

Formula & Concept
There are 30 students in a class. The average age of first 10 students is 12.5 years. The average age of the remaining 20 students is 13.1 years. The average age (in years) of the students of the whole class is :
Solution 
91
Discuss

Formula & Concept
The average of marks in Mathematics for 5 students was found to do 50. Later, it was discovered that in the case of one student the marks 48 were misread as 84. The correct average is :
Solution 
92
Discuss

Formula & Concept
The average marks obtained by a class of 60 students is 65. The average marks of half of the students is found to be 85. The average marks of the remaining students is :
Solution 
93
Discuss

Formula & Concept
In the first 10 overs of a cricket game, the run rate was only 3.2. The run rate in the remaining 40 overs to reach the target of 282 run is :
Solution 
94
Discuss

Formula & Concept
The average height of 30 boys out of a class of 50 is 160 cm. If the average height of the remaining boys is 165 cm, the average height of the whole class (in cm) is :
Solution 
95
Discuss

Formula & Concept
In an exam, the average marks obtained by Jhon in English, Math, Hindi and Drawing were 50. His average mark in Maths, Science, Social Studies and Craft were 70. If the average mark in all seven subjects is 58, his score in Maths was 
Solution 
96
Discuss

Formula & Concept
30 pens and 75 pencils altogether were purchased for Rs. 510. If the average price of a pencil was Rs. 2, what was the average price of a pen ?
Solution 
97
Discuss

Formula & Concept
The average age of 30 students of a class is 14 years 4 months. After admission of 5 new students in the class the average becomes 13 years 9 months. The youngest one of the five new students is 9 years 11 months old. The average age of the remaining 4 new students is :
Solution 
98
Discuss

Formula & Concept
The average age of husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was 20 years. The present age of the husband is :
Solution 
99
Discuss

Formula & Concept
The average of 10 items was found to be 80 but while calculating, one of the items was counted as 60 instead of 50. Then the correct average would have been :
Solution 
100
Discuss

Formula & Concept
The average age of 24 boys and their teacher is 15 years. When the teacher's age is excluded, the average age decreases by 1 year. The age of the teacher is :
Solution 
101
Discuss

Formula & Concept
The average age of four boys A, B, C and D is 5 years and the average age A, B, D, E is 6 years. C is 8 years old. The age of E is (in years) :
Solution 
102
Discuss

Formula & Concept
A librarian purchased 50 storybooks for his library. But he saw that he could get 14 books more by spending Rs. 76 more but per book average becomes Rs. 1 less. The average price (in Rs.) of each book he bought, was :
Solution 
103
Discuss

Formula & Concept
A student finds the average of 10, 2 digits numbers. If the digits of one of the numbers interchanged, the average increases by 3.6. The difference between the digits of the 2 digits number is :
Solution 
104
Discuss

Formula & Concept
The mean of 100 observations was calculated as 40. It was founder later on that one of the observation was misread as 83 instead of 53. The correct mean is :
Solution 
105
Discuss

Formula & Concept
Sachin Tendulkar has a certain average for 11 innings. In the 12th innings he scores 120 runs and thereby increases his average by 5 runs. His new average is :
Solution 
106
Discuss

Formula & Concept
The average age of husband and his wife was 23 years at the time of their marriage. After five tears they have a oneyear old child. The average age of the family of three, when the child was born, was
Solution 
107
Discuss

Formula & Concept
The present age of a father is 3 years more than three times the age of his son. Three years hence, father's age will be 10 years more than twice the age of the son. The father's age is :
Solution 
108
Discuss

Formula & Concept
The average (arithmetic mean) of 330, 360 and 390 is :
Solution 
109
Discuss

Formula & Concept
A set A consists of integers 27, 28, 30 and 33. If integer k is included in the set, the average of set A will increase by 30%. What is the value of integer k ?
Solution 
110
Discuss

Formula & Concept
The average age of 40 students of class is 18 years. When 20 new students are admitted to the same class, the average age of the students of the class is increased by 6 months. The average age of newly admitted students is ?
Solution 
111
Discuss

Formula & Concept
The mean weight of 34 students of a school is 42 kg. If the weight of the teacher be included, the mean rises by 400 grams. Find the weight of the teacher (in kg.)
Solution 
112
Discuss

Formula & Concept
Five years ago, the average age of P and Q was 25. The average age of P, Q and R today is 25. Age of R after 5 years will be :
Solution 
113
Discuss

Formula & Concept
If the mean of 4 observations is 20, when a constant 'c' is added to each observation, the mean becomes 22. The value of c is :
Solution 
114
Discuss

Formula & Concept
The average age of 30 students is 9 years. If the age of their teacher is included, the average age becomes 10 years. The age of the teacher (in years) is :
Solution 
115
Discuss

Formula & Concept
The average age of 20 boys in a class is 12 years. 5 new boys are admitted to the class whose average age is 7 years. The average age of all the boys in the class becomes:
Solution 
116
Discuss

Formula & Concept
The frequency distribution data is given below. If the average age is 17 years, the value of m is
Solution 
117
Discuss

Formula & Concept
The average of six numbers is 3.95. The average of two of them is 3.4, while the average of the other two is 3.85. The average of the remaining two numbers is :
Solution 
118
Discuss

Formula & Concept
If the arithmetic mean of 7, 5, 13, x and 9 is 10, then the value of x is :
Solution 
119
Discuss

Formula & Concept
3 years age, the average age of a family of 5 members was 17 years. A baby having been born, the average age of the family is same today. The present age of the baby is :
Solution 
120
Discuss

Formula & Concept
If the average of 5 consecutive integers is x then, find the average of next to next 5 consecutive integers.
Solution 
121
Discuss

Formula & Concept
The average age of P, Q and R is 15 years more than R's age. If the total age of P and Q together is 39 years, then R's age is ?
Solution 
122
Discuss

Formula & Concept
Find the average of 1.11, 0.01, 0.101, 0.001, 0.11 = ?
Solution 
123
Discuss

Formula & Concept
The average of 9 observations was found to be 35. Later on, it was detected that an observation 81 was misread as 18. The correct average of the observation is 
Solution 
124
Discuss

Formula & Concept
Out of 20 boys, 6 are each of 1 m 15 cm height, 8 are of 1 m 10 cm and rest of 1 m 12 cm. The average height of all of them is :
Solution 
125
Discuss

Formula & Concept
The average of the largest and smallest 3 digits numbers formed by 0, 2 and 4 would be :
Solution 
126
Discuss

Formula & Concept
The average of five numbers is 7. If three new numbers would be added, then the new average comes out to be 8.5. What is the average of those three new numbers ?
Solution 
127
Discuss

Formula & Concept
The average age of a family with 5 members is 28. If one of the 5 members of age 20 is excluded the average age of the family becomes 
Solution 
128
Discuss

Formula & Concept
The average of 6 observations is 45.5. If one new observation is added to the previous observations, then the new average becomes 47. The new observation is :
Solution 
129
Discuss

Formula & Concept
The average pocket money of 3 friend A, B, C is Rs. 80 in a particular month. If B spends double and C spends triple of what A spends during that month and if the average of their unspent pocket money is Rs. 60, then A spends (in Rs.)
Solution 
130
Discuss

Formula & Concept
The average age of group of 20 girls is 15 years and that of another group of 25 boys it is 24 years. The average age of the two groups mixed together is :
Solution 
131
Discuss

Formula & Concept
The average of nine number is 50. The average of first five numbers is 54 and that of the last three numbers is 52. Then the sixth number is :
Solution 
132
Discuss

Formula & Concept
From a class of 42 boys, a boy aged 10 years goes away and in his place, a new boy is admitted. If on account of this change, the average age of the boys in that class increases by 2 months, the age of the newcomer is :
Solution 
133
Discuss

Formula & Concept
In a primary school the average weight of male students is 65.9 kg and the average weight of female students is 57 kg. If the average weight of all the students ( both male and female ) is 60.3 kg and the number of male students in the school is 66, what is the number of female students in the school?
Solution 
134
Discuss

Formula & Concept
The average monthly income of P and Q is Rs. 6000; that of Q and R is Rs. 5250; and that P and R is Rs. 5500. What is P’s monthly income?
Solution 
135
Discuss

Formula & Concept
The average weight of a group of 75 girls was calculated as 47 kgs. It was later discovered that the weight of one of the girls was read as 45 kgs. Whereas her actual weight was 25 kgs. What is the actual average weight of the group of 75 girls? ( Rounded off to two digits after decimal).
Solution 
136
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Formula & Concept
Find the average of the following sets of scores:385, 441, 876, 221, 536, 46, 291, 428
Solution 
137
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Formula & Concept
If 25a + 25b = 115, what is the average of a and b?
Solution 
138
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Formula & Concept
The average of two numbers is XY. If one number is X, the other is
Solution 
139
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Formula & Concept
The average weight of a class of 24 students is 35 kg. If the weight of the teacher be included, the average rises by 400 g. The weight of the teacher is 
Solution 
140
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Formula & Concept
The average age of an adult class is 40 years. 12 new students with an average age of 32 years join the class, thereby decreasing the average by 4 years. The original strength of the class was
Solution 
141
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Formula & Concept
The average of the first five multiples of 3 is
Solution 
142
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Formula & Concept
The average of X1, X2 and X3 is 14. Twice the sum of X2 and X3 is 30. What is the value of X1?
Solution 
143
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Formula & Concept
The average sale of car dealership was 15 cars per week. After a promotional scheme the average sale increased to 21 cars per week. The percentage increased in the sale of cars was
Solution 
144
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Formula & Concept
The average age of the mother and her six children is 12 years which is reduced by 5 years if the age of the mother is excluded. How old is the mother ?
Solution 
145
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Formula & Concept
The average age of the boys in a class is 16 years and that of the girls is 15 years. The average age for the whole class is
Solution 
146
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Formula & Concept
Amount five people with monthly income (in Rs.) 15000, 26000, 16000, 19000, 50000, how many will have income less than the mean income of five people?
Solution 
147
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Formula & Concept
If the arithmetic mean of 0, 5, 4, 3 is a, that of 1, 0, 1, 5, 4, 3 is b and that of 5, 4, 3 is c, then the relation between a, b, and c is
Solution 
148
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Formula & Concept
In a family, the average age of a father and a mother is 35 years. The average age of the father, mother and their only son is 27 years. What is the age of the son?
Solution 
149
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Formula & Concept
Find the average of all the numbers between 6 and 34 which are divisible by 5 
Solution 
150
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Formula & Concept
The mean of 25 observations was found to be 78.4. But later on it was found that 96 were misread as 69. The correct means is
Solution 
151
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Formula & Concept
The average temperature for the first four days of a week is 40.2° C and that of the last four days is 41.3° C. If the average temperature for the whole 40.6°C, then the temperature on the fourth day is
Solution 
152
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Formula & Concept
The average of five numbers is 306.4. The average of the first two numbers is 431 and the average of the last two numbers is 214.5. What is the third number?
Solution 
153
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Formula & Concept
The average of six numbers is x and the average of three of these is y. If the average of the remaining three is z, then
Solution 
154
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Formula & Concept
The average of the first 100 positive integers is
Solution 
155
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Formula & Concept
After replacing an old member by a new member, it was found that the average age of five members of a club is the same as it was 3 years ago. What is the difference between the ages of the replaced and the new member?
Solution 
156
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Formula & Concept
The average weight of 8 men is increased by 1.5 kg when one of the men, who weight 65 kg is replaced by a new man. The weight of the new man is
Solution 
157
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Formula & Concept
Total expenses of a boarding house are partly fixed and partly varying linearly with the number of boarders. The average expense per boarder is Rs. 700 when there are 25 boarders and Rs. 600 when there are 50 boarders. What is the average expense per boarder when there are 100 boarders?
Solution 
158
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Formula & Concept
A shop of electronic goods is closed on Monday. The average daily sales for remaining six days of a week is Rs. 15,640 and the average sale of Tuesday to Saturday is Rs. 14,124. The sales on Sunday is 
Solution 
159
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Formula & Concept
The average expenditure of a man for the first five months is Rs. 1200 and for the next seven months is Rs. 1300. If he saves Rs. 2900 in that year, his monthly average income is
Solution 
160
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Formula & Concept
The average weight of 21 boys was recorded as 64 kg. If the weight of the teacher was added, the average increased by 1 kg. What was the teacher’s weight?
Solution 
161
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Formula & Concept
In a school with 600 students, the average age of the boys is 12 years and that of the girls is 11 years. If the average of the school is 11 years 9 months, then the average the number of girls in the school is :
Solution 
162
