A sum of money under compound interest doubles itself in 4 years. In how many years will it become 16 times itself?
None of these
if time is constant then the ratio of principal and amount is always constant in compound interest .
in 4 years sum become doubled P become 2P
p _____4 years ____2p___4years _____8p ___4 years ____ 16 p
4+4+4+4= 16 years