In how many years will the simple interest on a certain sum be 4.05 times the principal at 13.5% per annum?
Time = 30 years
SI = 4.05P.SI = (P × R × T)/100 ⇒ 4.05P = (P × 13.5 × T)/100.T = (4.05 × 100)/13.5 = 30 years.