Question

the sum f a boy and his elder brother is 12years and the sum of the square of their ages in 74 in years .find their ages

Answer 1

Let, younger brother be X and Elder brother be Y.

Then,

X + Y = 12,

X^2 + Y^2 = 74

So, Now if we will give square on both side in 1st equation then,

( X + Y)^2 = (12)^2

:• X^2 + Y^2 + 2XY = 144

:• 74 + 2XY = 144

:• 2XY = 144 - 74

:• 2XY = 70

:• XY = 70/2

:• XY = 35

So, X*Y = 5*7

X is younger so he is 5 years old and Y is Elder so he is 7 years old.

Hope it will help you. For your help I did attach a image with this answer if you can't able to understand here you can understand in image. THANK YOU