Rs agarwal quantitative aptitude

Question

The compound interest on a certain sum is  832 for 2 years and simple interest on same sum for 2 years is 800. The difference between compound interest and simple interest after 3 years will be?  

A)  48 B) 66.56 C) 98.56 D) None

Please explain.

Answer 1

you know SI is same for every year

ie. if 2yr SI is 800 then one year SI is 400

but in CI interest applied on previous interest also

difference between 2 yr CI and SI is 832-800=32

Comments

I found same answer on net that's why I posted it here because i was not able to understand this.  

Why do we take 400 as P and interest as 32 i.e 432-400