Question

The compound interest on a certain sum for 2 years at 10% per annum is rs. 525. the simple interest on the same sum for double the time at half the rate percent per annum is:

Answer 1

P + 525 = P (1 + 0.1)^2

P = 525 / 0.21

P = 2500

Now,
Simple Interest = 2500 * 4 * 5%
= 500