Bob and Alice have 35 pumpkin pies altogether. Bob and Catherine have 55 pumpkin pies altogether. If Catherine has 3 times as many pumpkin pies as Alice, how many pumpkin pies does Alice have?
Since Bob has a fixed number of pumpkin pies, Catherine must have 55 35 = 20 more pumpkin pies than Alice.
Since Catherine has 3 times as many pumpkin pies as Alice, and since Catherine has 20 more pumpkin pies than Alice, you must find a number such that when you add 20 to it, it is 3 times bigger than it was originally. You can find this number using the formula: number = (difference) ÷ (times bigger 1)
Times bigger: 3
Number: 20 ÷ (3 1) = (20 ÷ 2) = 10
Alice has 10 pumpkin pies.
If you dont know this formula, you can also find the number by trial and error. Start with a number, add 20 to it, and see if it is 3 times bigger.