Question

The sum of two positive integers is 80 & difference between them is 20. Then what is difference of squares of those numbers ?

Answer 1

Let the positive integers be X and Y .

Then,

X + Y = 80 ---------- first equation

X - Y = 20 --------- second equation

X + X = 80 + 20

2x = 100

X= 100/2

X = 50

Value of X = 50

Then, value of Y = 30

Square of 50 = 2500

square of 30 = 9900

Difference = (9950-2500) = 7450