a firm offers a packed lunch box group discount for orders exceeding 15. two firms are taking advantage of this offer. sales to company a averages $15, 000 of annual sales, has a 22% profit margin and an expected lifetime of 8 years. company b averages $11, 000 of annual sales, has a 25% profit margin and an expected lifetime of 90 years. which is the more important customer based on the higher expected lifetime value? assume a 7% discount rate.