Question

A certain sum of money becomes three times of itself in 20 years at simple interest. In bow many years does it become double of itself at the same rate of simple interest?

Answer 1

Simple Interest Formula is A = PRT (A = Amount, P = Principal, R = Rate, T = Time or Period)

Let the Principal amount be x

So, 3x = x * R * 20 - - - - equation 1,

and 2x = x * R * T - - - - -equation 2

Multiply equation 1 by 2 and equation 2 by 3 and subtract Eq 2 from Eq 1

we get 40 R - 3RT = 0

∴ T = 40/3 years