Example 3

Jonah wants to buy matching shirts for the freshman class officers. Each shirt costs $15, plus a standard shipping fee of $8 for any number of shirts ordered. Determine the slope of the line that passes through the points of the total cost of 1 shirt to 5 shirts. Explain what the slope means in the context of the problem. Finally, use the slope to determine how many shirts can be purchased for $115. Assume there is no sales tax.