Calculate tiered cost and break-even

A vendor charges a fixed setup fee of $500 per order. The unit price is $12 for the first 1,000 units and $9 for each additional unit beyond 1,000. Shipping costs $0.80 per unit for the first 2,000 units and $0.50 for each unit thereafter. (a) Write a formula for total cost as a function of quantity q. (b) Compute total and average cost per unit for q = 1,600 and q = 3,200. (c) If your resale price is $15 per unit, what is the break-even quantity? Show steps.