Quiz Discussion

The average of the first five multiples of 3 is-

• 1] 3
• 2] 9
• 3] 12
• 4] 15

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 :

• 1] 12.5 years
• 2] 12.7 years
• 3] 12.8 years
• 4] 12.9 years

When the average age of a couple and their son was 42 years, the son married and got a child after one year. When the child was 5 years old, the average age of the family became 36 years. What was the age of daughter-in- law at the time of their marriage ?

• 1] 23 years
• 2] 24 years
• 3] 25 years
• 4] 26 years

The average of two numbers is XY. If one number is X, the other is-

• 1]

  Y/2

• 2]

  Y

• 3]

  2XY - X

• 4]

  X (Y - 1)

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?

• 1] 74
• 2] 75
• 3] 69
• 4] 78

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:

• 1] 50
• 2] 60
• 3] 70
• 4] 65

Find the average of the first 40 natural numbers.

• 1]

  21

• 2]

  20.5

• 3]

  21.5

• 4]

  None Of These

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 ?

• 1] 68
• 2] 79
• 3] 73.75
• 4] 75.25

The average of four consecutive even numbers is 15. The 2nd highest number is :

• 1] 12
• 2] 18
• 3] 14
• 4] 16

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