Dear prashanth.guru,
I'm happy to help with this.

We know that r = 5, so this gives us the equation

5 = (4x + 8y)/(x + y)

Multiply both sides by that denominator, (x + y)

5*(x + y) = 4x + 8y
5x + 5y = 4x + 8y
x = 3y

So, we see that x must be three times y. So, start with the smallest y: if y = 21, then x = 3*21 = 63, which is not an option. Next y, y = 32, means x = 3*32 = 96 --- bingo! That's it. OA = {x = 96, y = 32}

Does this make sense?

BTW, you may find this helpful:
https://magoosh.com/gmat/2012/gmat-integ ... ing-ebook/

Mike