A firm sells 1000 units per week. It charges $15 per unit, the average variable costs are $10, and the average costs are $25. In the long run, the firm should a. Shut-down because it is cost effective to pay off the remaining fixed costs b. Continue operating as the firm is covering all the variable costs and some of the fixed costs c. Shut-down as the firm is making a loss of $10,000 per week d. Shut-down as price is lower than average cost

When a company produces and sells x thousand units per week, its total weekly profit is p thousand dollars, where upper p equals startfraction 800 x over 100 plus x squared endfraction . the production level at t weeks from the present is x equals 4 plus 2 t. find the marginal profit, startfraction dp over dx endfraction and the time rate of change of profit, startfraction dp over dt endfraction . how fast (with respect of time) are profits changing when tequals8?