# Find the 10 Times of Rate of Interest.

A sum of money becomes 9 times in 20 years. Find the 10 times of rate of interest.

- 350%
- 45%
- 400%
- 250%

**Answer: (2) 45 %**

**Explanation:-**

**Given-**

Time = 20 years, Let the principal be X & Rate = R %

Then, Amount = 9 X

Simple Interest = 9 X – 8 X

**Formula-**

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

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

Then, 8 X = X x 20 x R/100

8 = R/5

R = 40 %

If amount is 10 times .

Then, Simple Interest = 10 X – X = 9 X

9 X = X x 20 x R/100

9 = R/5

R = 45 %

Hence, the answer is (2) 45 %.