Question 1178033
The prob'y density function of {{{X}}} (or {{{Y}}}) is {{{f(x) = 1/4}}}, being distributed uniformly.

==> {{{E(X) = (1/4)*(int(x,dx,8,12) )= 10}}}.  Similarly, {{{E(Y) = 10}}}, Y being identical distributionally to X.

==> {{{E(A) = E(XY) = E(X)*E(Y) = 10*10 = 100}}}, since X and Y are independent random variables.