Question

A sum of money lent out at c.i. at a certain rate per annum becomes 3 times of itself in 8 years. Find in how many years will the money become 27 times of itself at the same rate.

Answer 1

72 years: because, 3 times in 8 years, when 3 becomes 27 = 3×9
then the number 8 must be multiplied also to 9 : 9×8=72 due to which lhs=rhs