Question 163881
{{{12000*(l+r)^2 = 27000}}}
{{{12*10^3*(1+r)^2 = 27*10^3}}}
take the log to the base 10 of both sides
{{{log(12) + 3 + log((1 + r)^2) = log(27) + 3}}}
{{{1.079 + 3 + 2*log(1 + r) = 1.431 + 3}}}
Subtract {{{4.079}}} from both sides
{{{2*log(1+r) = .352}}}
{{{log(1+r) = .176}}}
This is the same as saying
{{{1 + r = 10^.176}}}
{{{1 + r = 1.500}}}
{{{r = .5}}}
This says his average annual rate of return was 50%