Aptitude Hack#60(24-4-19)

Question:

What is the sum of two consecutive odd numbers, the difference of whose squares is 56?

A) 30

B) 28

C) 34

D) 32


Answer: B) 28 

Explanation:

Let the no. be x and (x +2).
Then (x +2)^2 – x^2 = 56
4x + 4 = 56
x + 1 = 14
x = 13
Sum of numbers = x + (x +2) = 28


Alternate solution:-

Let two numbers be x and y.
x^2 + y^2 =56
(x-y)(x+y)=56
//x-y would be 2 as the numbers odd and they are consecutive.
//we have asked sum of numbers i.e x+y
(x+y)=56/2=28.