Icelantic manufactures and sells Colorado-made skis. The firm wants to produce a limited edition of skis to celelbrate Golden Colorado. The firm estimates that the fixed cost of producing this batch of skis is $7,500 and the variable cost is 304 per pair of skis. The firm further estimates that the revenue from selling x pairs of skis is R(x) =

300x + 4000ln(1+x).

Answer the following questions:

(A) What is Icelantic's marginal profit from selling x pairs of this limited edition of skis?

Marginal profit is

(B) What is the number of ski pairs that maximizes Icelantic's profit?

Optimal number of ski pairs is