Hello, at first had this problem:

A mountain lake in national park is stocked each spring with two species of fish, S1 and S2. The average weight of the fish stocked is 4 pounds for S1 and 2 pounds for S2. Two foods, F1 and F2, are available in the lake. The average requeriment of a fish of species S1 is 1 unit of F1 and 3 units of F2 each day. The corresponding requeriment of S2 is 2 units of F1 and 1 unit of F2.

**a). Suppose that 1000 units of F1 and 1800 units of F2 are available daily in example previous. How should the lake be stocked to maximize the weight of fish supported by the lake?**
Well, I have already found the solution, graphical method using the search

Maximize

subject to restrictions

And the solution is

The question I have is to resolve this part:

In problem previous, how should the lake stocked to maximize the total number of fish supported by the lake?.