How much time will it take for an amount of Tk. 450 to yield Tk. 81 as interest at 9% per annum of simple interest?

Question: How much time will it take for an amount of Tk. 450 to yield Tk. 81 as interest at 9% per annum of simple interest?

Solution:
I = Pnr
⇒ 81 = 450 × n × 9/100
∴ n = (81 × 100)/(450 × 9)
= 2 years