Based on what is written, Patty's Pies used 5 cups of peaches per 1 peach pie. As you can see, for every 1 pie in each example, 5 cups of peaches are used, 10 cups for 2 pies, 15 cups for 3 pies, etc. For 9 pies, multiply 5*9 to get 45. They would use 45 cups of peaches to make 9 pies if they continued to follow the same pattern.
I hope this helps :)