cumulative probability continued.... Ok. I have 25 gumball machines with red or green gumballs. Each machine has a different percentage of each. Number 1 has 70% red, 30% green. Number 2 has 95% red, 5% green, and so on. I buy 1 gumball from each an drop it into a bag. Then reach into the bag and pull a random gumball. How to calculate probability Red or Green from the bag?