It is given that James has 5 friends who are available to go to a baseball game with him, but James has only has 2 extra tickets. This is a perfect example of a combinations question and we have been asked to choose 2 from a given 5. This can be spoken of as: Given 5 choose 2 and can be represented mathematically as a Combination:
[tex] ^5C_2=\frac{5!}{2!(5-2)!}=\frac{5!}{2!3!} =\frac{5\times 4\times 3!}{2\times 3!}=10 [/tex]
Thus, James has 10 different choices to invite 2 friends.
