(1 point) Suppose that for a company manufacturing calculators, the coat, and revenue equations are given by 1 C=90000+20x, R=300-:0, dx where the production output in one week is x calculators. If the production rate is increasing at a rate of 500 calculators, t = 500, when the production output is 6000 calculators, that is x = 6000. Find each of the following when x = 6000: Rate of change in cost E = a; f _. Rate of change in revenue 2]: = ES (11' Rate of change in prot d = t