Let $\mbox{div }\vec F = 4(3-x)$ and $0\le a, b, c\le 11$.

(a) Find the flux of $\vec F$ out of the rectangular solid $0\le x\le a$, $0\le y\le b$, $0\le z\le c$.
flux =

(b) For what values of $a$, $b$, $c$ is the flux largest?
$a =$
$b =$
$c =$

(c) What is that largest flux?
flux =