At a school fair, you can toss coins into cups to earn points. If you earn 100 points or more you win a prize. The cups are worth 15, 20, 25, and 30 points. If you get 4 tosses and can stop whenever you reach 100 points, what are all the possible combinations of cups that you could toss coins into to receive a prize?

Create a chart to organize your answer.
How do you know you have all possibilities?

2 20's and 2 30's