I need help with the following problem:

Exercise 7-7 Riggs Company purchases sails and produces sailboats. It currently produces 1,290 sailboats per year, operating at normal capacity, which is about 80% of full capacity. Riggs purchases sails at $260 each, but the company is considering using the excess capacity to manufacture the sails instead. The manufacturing cost per sail would be $95.69 for direct materials, 588.14 for direct labor, and $90 for overhead. The $90 overhead includes $78,100 of annual fixed overhead that is allocated using normal capacity. The president of Riggs has come to you for advice. It would cost me $273.83 to make the sails, she says, but only $260 to buy them. Should I continue buying them, or have! missed something, Prepare a per unit analysis of the differential costs. If Riggs suddenly finds an opportunity to rent out the unused capacity of its factory for $77,600 per year, would your answer to part (a) change