Quiz Discussion

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:

• 1] 8.2 years
• 2] 9.5 years
• 3] 12.5 years
• 4] 11 years

Average of a, b, and c is 11; average of c, d and e is 17; average of e and f is 22 and average of e and c is 17. Find out the average of a, b, c, d, e and f.

• 1]

  \(15\frac{2}{3}\)

• 2]

  \(18\frac{1}{2}\)

• 3]

  \(16\frac{1}{2}\)

• 4]

  None of these

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 :

• 1] 60
• 2] 62
• 3] 65
• 4] 66

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?

• 1] Rs. 540
• 2] Rs. 550
• 3] Rs. 570
• 4] Rs. 580

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 

• 1]

  x=y+z

• 2]

  2x=y+z

• 3]

  x=2y+2z

• 4]

  x=2yz

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?

• 1] 74%
• 2] 75%
• 3] 69%
• 4] 72%

The average of 11 players of a cricket team is decreased by 2 months when two of them aged 17 years and 20 years are replaced by two new players. The average age of the new players is-

• 1] 17 years 1 month
• 2] 17 years 7 months
• 3] 17 years 11 months
• 4] 18 years 3 months

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?

• 1] 72
• 2] 74
• 3] 70
• 4] 76

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.)

• 1] 55 kg
• 2] 57 kg
• 3] 66 kg
• 4] 56 kg

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 :

• 1] 15
• 2] 25
• 3] 20
• 4] 10