Question 1033456
We need to find {{{alpha}}} such that 

{{{P(X >= alpha) = 0.15}}}

<==> {{{P((X-72)/12 >= (alpha - 72)/12) = P(Z >=(alpha - 72)/12) = 0.15}}}

==> {{{(alpha - 72)/12 = 1.035}}}

==> {{{alpha = 84.42}}}