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%.