Production costs for manufacturing running shoes consist of a fixed overhead of $650,000 plus variable costs of $20 per pair of shoes. Each pair of shoes sells for $70.

(a) Find the total cost, C(q), the total revenue, R(q), and the total profit, π(q), as a function of the number of pairs of shoes produced, q.

(b) Find the marginal cost, marginal revenue, and marginal profit.

(c) How many pairs of shoes must be produced and sold for the company to make a profit?