### Quantitative Aptitude - Average

#### Question - 1

David obtained 76, 65, 82, 67 and 85 marks (out of 100) in English, Mathematics, Physics, Chemistry and Biology. What are his average marks?

• A 65
• B 69
• C 72
• D 76
• E None of these

#### Question - 2

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 of them are correct in their estimation, what is the average of different probable weights of Arun?

• A 67 kg
• B 68 kg
• C 69 kg
• E None of these

#### Question - 3

The average of 20 numbers is zero. Of them at the most, how many may be greater than zero?

• A 0
• B 1
• C 10
• D 19

#### Question - 4

Find the average of all the numbers between 6 and 34 which are divisible by 5.

• A 18
• B 20
• C 24
• D 30

#### Question - 5

The average of the first five multiples of 3 is:

• A 3
• B 9
• C 12
• D 15

#### Question - 6

The average of the first nine prime numbers is :

• A 9
• B 11
• C $11{1\over 9}$
• D $11{2\over 9}$

#### Question - 7

A student was asked to find the arithmetic mean of the numbers 3, 11, 7, 9, 15, 13, 8, 19, 17, 21, 14 and x. He found the mean to be 12. What should be the number in place of x?

• A 3
• B 7
• C 17
• D 31

#### Question - 8

The average of 2, 7, 6 and x is 5 and the average of 18, 1, 6, x and y is 10. What is the value of y?

• A 5
• B 10
• C 20
• D 30

#### Question - 9

If the mean of 5 observation x, x+2, x+4, x+6 and x+8 is 11, then the mean of the last three observation is :

• A 11
• B 13
• C 15
• D 17

#### Question - 10

If the mean of a, b, c is M and ab+bc+ca=0, then the mean of a2, b2, c2 is :

• A M2
• B 3M2
• C 6M2
• D 9M2