A man invests a certain sum of money at the rate of interest 10% for 2 years. After 2 years, he earns Rs. 400 as a simple interest. If he invests the same sum of money at the same rate for 2 years on compound interest, then find how much percentage of the compound interest is greater than the simple interest?
1
7.5%
2
10%
3
5%
4
20%
5
15%