For Material 1, we have the following graph:
Where the parabola represents Revenue and the straight line represents Costs.
For Material 2, we have:
For Material 3, we have:
As you can observe, material 2 gives the highest revenue. For a price of 80, the revenue is 6.4 million. Now, we use the linear equation to find the cost.
[tex]y=4,000,000-10,000\cdot80=4,000,000-800,000=3,200,000[/tex]Then, we subtract the revenue and the cost to find the profit.
[tex]6,400,000-3,200,000=3,200,000[/tex]Hence, profit is 3,200,000.