



 
Andre, I am going to start with part b). They have two costs. An initial cost of 750$ and then 5$ for each shirt. Thus their costs are
They charge 15$ for each shirt so their revenue is
The profit is the revenue minus the cost so what is the profit? For part a) you don't know how many shirts they need to sell so call it x. What are the costs for x shirts? What is the revenue for x shirts? If they just break even then the costs and the revenue are equal. Solve for x. I hope this helps,  


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