# Math Help - simple probability example

1. ## simple probability example

hey,

i have the following question which i cannot answer.

Ten Students A,B,..... are in a class. A committee of three is chosen at random to represent the class.
Find the following probabilities:

a) A belongs to the committee
b) B belongs to the committee
c) A and B belong to the committee
d) A or C belong to the committee

I dont have a clue on how to approach this question.

The are 10_C_3 combinations of choosing the members, but is that necessary?

d) This depends a bit on how the question is, is it one of them only, or can it also be both of them. If it's the second one, this is the formula to get you started. $P(A \cup C) = P(A) + P(C) = P(A \cap C)$