Quiz Discussion

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.

• 1] 125 km/hr
• 2] 75 km/hr
• 3] 135 km/hr
• 4] 120 km/hr

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 :

• 1] 25
• 2] 21
• 3] 23
• 4] 28

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 :

• 1] 40.2
• 2] 40.8
• 3] 42.8
• 4] 48.2

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 :

• 1] 38 years
• 2] 39 years
• 3] 40 years
• 4] 41 years

The average of the first five multiples of 3 is-

• 1] 3
• 2] 9
• 3] 12
• 4] 15

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?

• 1] 52
• 2] 108
• 3] 321
• 4] Cannot be determined
• 5] None of these

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?

• 1] 10 years
• 2] 10.5 years
• 3] 11 years
• 4] 12 years

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?

• 1] Rs. 5, Rs.7.50
• 2] Rs. 8, Rs. 12
• 3] Rs. 16, Rs. 10
• 4] Rs. 12, Rs. 14

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 ?

• 1] 19 years
• 2] 19 years 6 months
• 3] 20 years
• 4] 20 years 6 months

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?

• 1]

  4

• 2]

  5

• 3]

  6

• 4]

  7