In its next production period, Valu$-$Com has $80,000$ square inches of PC board, $100,000$ resistors, $30,000$ memory chips, and $5,000$ hours of assembly time available. The company can sell all the product it can manufacture, but the marketing department wants to be sure the company produces at least $500$ units of each product and at least twice as many FastLink cards as HyperLink cards while maximizing profit.

a$.$Formulate an LP model for this problem.

b$.$Create a spreadsheet model for this problem and solve it using Solver.

c$.$What is the optimal solution?

d$.$Could Valu$-$Com make more money if it schedules assembly workers to work overtime?