Suppose that for a company manufacturing calculators, the cost, revenue, and prot equations are given by 2 X C=80,000+40X, R=300xE, P=R-C where the production output in 1 week is x calculators. If production is increasing at a rate of 500 calculators per week when production output is 6,000 calculators. Find the rate of increase (decrease) in cost, revenue, and profit. (E A) Costs are |:| at the rate of $|:| per week at this production level. (Simplify your answer.)