Two ice cream shops are located across the street from one another on a busy street. • At Max's Ice Cream shop, you can buy a sundae with unlimited toppings for $5 per sundae.
• At Mary's Ice Cream shop, you can buy a sundae by paying $3.50 for the ice cream and then $0.75 for each
topping.
At which ice cream shop is the cost of the sundaes (including the toppings), proportional to the number of
sundaes purchased? Justify your answer with tables, graphs, or an explanation.