(1 point) Suppose that for a company manufacturing calculators, the cost, and revenue equations are given by C = 70000 + 40r, R = 300 30 where the production output in one week is a calculators. If the production rate is increasing at a rate of 500 calculators when the production output is 6000 calculators, find each of the following: Rate of change in cost = Rate of change in revenue = Rate of change in profit =