Find Solved Quantitative Aptitude Questions from Averages Chapter.
1) The average heights of three poles  x,y,z is 45 cms. If average height of x and y is 40 cm and that of y and z

is 43 cm, can you find the height of the second pole y.

a) 30 cms
b) 31 cms
c) Cannot be determined

Answer: Sum of heights of three poles x,y and z = 45 x 3 = 135 cms = x + y + z
However, x + y = 2 X 40 cms = 80 cms and y + z = 2 x 43 cms = 86 cms
Solving the three equations we can get y = 31 cms

2) Find the average of first 10 odd numbers starting from 3.

a) 11
b) 12
c) 24

Answer:
Odd numbers form an arithmetic progression of the form, a, a+d, a+2d..... , where a = 3 and d = 2.
Average of n numbers in AP = (2a + (n - 1)d) / 2 . Therefore average of first 10 numbers is obtained by

substituting n = 10 in the above formula. We will get the answer 12.