The compound interest on a certain sum for 2 years at 10% per annum is Tk. The simple interest on the same sum for double the time at half the rate percent per annum is :

A Tk. 400

B Tk. 500

C Tk. 600

D Tk. 800

Correct Answer: Option B

The compound interest on a certain sum for 2 years at 10% per annum is Tk. 525.

C = P(1+r/100)n

525+P = P(1+ .1)2

=>P = 2500

For Simple Interest,

I = Pnr

= 2500X4X.05 = 500