What rate of interest compounded annually is required to triple an investment in 20 years?
The rate of interest required is %?
(1 . x)^20 = 3
20 ln (1 .x) = ln 3
ln (1 .x) = (ln 3)/20 = 0.0549306
( 1 .x) = e^0.549306 = 1.0564
x = 0.0564.
Answer is 5. 64 %