A small market orders copies of a certain magazine for its magazine rack each week. Let...

A small market orders copies of a certain magazine for its magazine rack each week. Let X = demand for the magazine, with pmf

Suppose the store owner actually pays $2.00 for each copy of the magazine and the price to customers is $4.00. If magazines left at the end of the week have no salvage value, is it better to order three or four copies of the magazine? [Hint: For both three and four copies ordered, express net revenue as a function of demand X, and then compute the expected revenue.]