Arithmetic Aptitude :: Simple Interest
9. Simple interest on a certain sum is 16/25 of the sum. Find the rate percent and time, if both are numerically equal.
Let sum = X. Then S.I. = 16x/25
Let rate = R% and Time = R years.
Therefore, x * R * R/100 = 16x/25 or R^2 = 1600/25, R = 40/5 = 8
So, Rate = 8% and Time = 8 years.