Question

in how many years does a sum of money becomes 4 times at simple interest rate of 10% p.a.

Answer 1

Let principle be P
Given,
r = 10, A = 4P, n = ?

A = P + Pnr/ 100
4P = P[ 1 + nr / 100]
4 = [ 100 + nr] / 100
400 = 100 + n(10)
300 = 10n
n = 30