Not to be rude or anything, but this problem is hard because it is from week 12 of introduction to counting and probability online class. It is an aops class so it is supposed to be pretty hard. I think the whole purpose of it is to learn, not get answers off the web. I think mellie has asked the answers to all the problems. Why are you here then, you ask? Well I wanted to see if you could actually get the answer from simply googling the exact problem. And I guess you can. Anyways I guess you are just wasting you/your parent's money if you paid for a class and just asked the answers in a forum.
