Suppose $\displaystyle \vec{G} $ is a vector field with the property that $\displaystyle div\vec{G} = 5 for 2 \leq ||\vec{r}|| \leq 14 $ and that the flux of $\displaystyle \vec{G} $ through the sphere of radius 4 centered at the origin is $\displaystyle 20\pi$. Find the flux of through the sphere of radius 12 centered at the origin.

I am really confused on where to start at this point