Simple Trick for Age MCQs

Q. The sum of ages of five children born at the intervals of three years each is fifty years. What is the age of the smallest child?

A. 2
B. 4
C. 8
D. 12
E. None of these

Solution:  The correct answer is B.

1st child  age  = x
2nd child age = (x + 3)
3rd child age = (x + 6)
4th child age = (x + 9)
5th child age = (x + 12)
#####################
 Sum of child ages = 50
#####################                                              

Let the ages of children be   x, (x + 3), (x + 6), (x + 9) and (x + 12) years.
Then, 
           x + (x + 3) + (x + 6) + (x + 9) + (x + 12) = 50

    By simplifying, we get 
       => 5x + 30 = 50
       => 5x +30 - 30 = 50 -30        => 5x =20
       => x = 20/5 
       => x = 4  

Hence, the smallest child age is 4.