# What will be the Rate % per Annum? If

On a certain, sum, the simple interest at the end of 12.5 years becomes 3/4 of the sum. What is the rate % per annum?

- 4%
- 5%
- 6%
- 8%

**Answer: (3) 6 %**

**Explanation:-**

Let the principal be P & the rate is R %.

Then, Simple Interest = 3 P /4

**Formula-**

**Simple Interest = P x R x T/100**

**Where, P = principal , R = rate, & T = time.**

Time = 12.5 = 25 / 2 years (Given)

Then, 3 P /4 = P x 25 x R /100 x 2

3 / 4 = R / 4 x 2

3 = R / 2

R = 3 x 2

R = 6 %.

Hence, the rate percent per annum is 6 %.