Ned needs to produce more of his two products in order to increase his net income and has found a way to increase the limited resource, machine hours. He has two products, hammers and screwdrivers.. The hammers have a contribution margin per unit of limited resource of $300 and a unit contribution margin of $150. The screwdrivers have a contribution margin per unit of limited resource of $280 and a unit contribution margin of $170. Ned can dedicate an additional 120 machine hours to production this month. Which product should he give the extra 120 hours to?

The answer is The hammers, because they provide additional contribution margin of $36,000.

But I want to know the steps. Please show the process.