# What will the rate of Interest? If

At simple interest a sum of money is doubled in 20 years. What is the rate of interest?

- 20%
- 4%
- 5%
- 10%

**Answer: (c) 5%
Explanation:-**

Let be the amount = P and Rate = R

According to question, P = P x R x 20/100

R = 5%

Hence, the rate of interest is 5%.