Let R(x) denote the revenue (in thousands of dollars) generated from the production of x units of computer chips per day, where each unit consists of 100 chips.

(a) Represent the following statement by equations involving R or R′: When 1200 chips are produced per day, the revenue is $22,000 and the marginal revenue is $.75 per chip.

(b) If the marginal cost of producing 1200 chips is $1.5 per chip, what is the marginal profit at this production level?