Continuing from the setup in the question linked above (and using the same symbols/variables), we have
The next part of the question asks to maximize this result - our target function which we'll call
- subject to 
.
We can see that
is quadratic in 
, so let's complete the square.
Since
are non-negative, it stands to reason that the total product will be maximized if 
vanishes because 
is a parabola with its vertex (a maximum) at (5, 25). Setting 
, it's clear that the maximum of will then be attained when are largest, so the largest flux will be attained at 
, which gives a flux of 10,800.
The next part of the question asks to maximize this result - our target function which we'll call
We can see that
Since