In a group of 10 batteries, 3 are dead. You choose 2 batteries at random.
a) Construct a probability distribution for the number of good batteries you get.

b) What is the expected number of good ones you get?

Hypergeometric.

The Hypergeometric Distribution (http://www.stat.tamu.edu/stat30x/notes/node67.html)

Has a good example you can follow.