Help with Probability, Combinatorics, and Binomial Probabilt

I’m struggling quite a bit with these topics and I’ve only briefly covered them in a class where they weren’t fully explained.
I was wondering if anyone would please tell me the methods for solving these problems, and problems like it so that I could do them on my own in the future –
1) A local club has for prizes to be given out. Three community organisations each nominate entry people for the prizes. If the prizes are given out randomly, what is the probability that they will all be given out to people from the same organization?
2) A class of seven needs to be split into a group of four and a group of three. There are two students who cannot be in the same group. How many different groups can be formed?
3) The probability that a student passes their Maths test is .8 and the probability that a student passes their Programming test is 0.6. If the probability that a student passes both is 0.55, what is the probability that they pass neither?
4) The probability that a certain brand of television does not need to be fixed under a one year waaranty is 0.95. If a business buys five of them, what is the probability that at most one will be needed to be fixed during the warranty period?
Thanks a lot for any and all help.
Answer #1
Edited. Sorry but I think I am wrong. Might try again later. MIGHT.