Suzan sees a bag of marbles, she grabs a handful at random. She has seen a bag containing three red marbles, four green ones, five white ones, and one purple one. She grabs seven of them. Find the probability of the following event, expressing it as a fraction in lowest terms. She has at least one green.
so far i have that C(13,7)=1716
so after that what would i have to do to get at least the one green probability.