Question 41762
{{{60 = 400/(1+r)^3}}}
or {{{(1 + r)^3 = 400/60 = 20/3}}}
or {{{(1+r) = (20/3)^(1/3) = 1.8821}}}
or r = 1.8821 - 1 = 0.8821


As simple as that!