# Find Out the Rate of Interest

The simple interest on a certain sum for 2 year is Rs 120 and compound interest is Rs. 129. Find the rate of interest

- 14%
- 15%
- 12%
- 12.5%

**Answer: (2) 15 %
**

**Explanation:-**

Simple Interest & compound Interest in first year are equal

Simple Interest for every year will be same.

Simple Interest of two years = Rs.120

Then, the simple interest of one year = 120/2

= Rs.60

Therefore, the compound interest of first year = Rs.60

The difference between simple interest and compound interest for second year = 129 – 120

= Rs.9

Therefore, Rs.9 is percent of 60 = 9 x 100/60

= 90/6

= 15 %

Then, the rate of interest is 15 %.

Hence, the answer is (2) 15 %.