Assume the following demand curve: Q = 50,400 1,200(P). Variable costs are estimated to be $25.37. Calculate total contribution margin at the optimal price. Round your answer to the nearest dollar.

Assume the following demand equation: Q = 755 - 20(P). Variable costs = $6. Calculate marginal revenue for the 251st unit. Round your final answer to the nearest dollar. (When you are calculating the two prices, do not round to less than 2 decimal places. In other words, you are safe to round each price to the nearest penny.)