Find the Price That Maximizes the Profit If the Demand

Short Answer

Find the price that maximizes the profit if the demand for a product varies from 100 at a price of $800 each to 400 at a price of $200 each. Also, 100 could be supplied at a price of $500 each, whereas 900 could be supplied for $1,300 each. Assume that supply and demand are linear.
$__________