(Required) Q. Juan Martinez played classical guitar professionally until his motorcycle accident left him disabled. After long months of therapy, he hired an experienced luthier (maker of stringed instruments) and opened a small shop that makes and sells Spanish guitars. The gitars sell for $600, and the fixed monthly operating costs are as follows: Rent and utilities $960 Wages and benefits of luthier $1,500 Other $900 Juan got confused when his accountant told him about contribution margin ratios, but he understood clearly that for every dollar of sales, $0.70 went to cover his fixed costs, and that anything past that point was pure profit. a. How many guitars does Juan have to sell each month to break even? b. Juan wishes to make $2.500 of operating profit each month. If so, how much sales revenue will Juan have to make