# At What Rate of Annual Simple Interest, a Sum will Amount to Five Times in 16 Years?

**Answer: (3) 25%**

**Explanation:-
**Let the principal be = Rs. X and rate = R%

**Formula-**

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

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

According to the question,

Simple interest = 5 X – X = 4 X & Time = 16 years

Then, 4 X = X x R x 16/100

4 = 4 R/25

R = 25%

Then, 25% of simple interest, a sum will amount to five times in 16 times.

Hence, the answer is (3) 25%.