3. Yang Manufacturing makes a product called Yin. The relevant range of operations is

between 2,500 units and 10,000 units of Yin per month. Per unit costs at two activity

levels are as follows: 5,000 units at $17.00 per unit; 7,500 units at $13.00 per unit.

Determine the cost formula that expresses the behaviour of Yang's total costs.