\begin{problem*}{24.11}
Four closed surfaces, $S_1$ through $S_4$, together with the charges
-$-2Q$, $Q$, and $-Q$ are sketched in Figure P24.11. (The colored
+$-2Q$, $Q$, and $-Q$ are sketched in Figure~P24.11. (The colored
lines are the intersections of the surfaces with the page.) Find the
electric flux through each surface.
% -2Q