Can someone please help with writing this out as equation?

The student council has decided to sell t-shirts with a school logo to promote school spirit. Amanda investigated 1 company that would charge $75 to make the printing screen for the shirts, and then $5.50 per shirt. Adam checked out a 2nd company that would charge a straight $7 per shirt. Which company's option would respresent a proprtional relationship? You should support your answer with an equation, a table of values, or a graph.