Word Problem

Question

Your sock drawer is a mess and contains 10 white socks, 12 black socks, and 4 red socks. How many socks would you have to pull out of the drawer to be sure you have a pair?

 

What is the probability that the first sock you pull out will be black and the second sock you pull out (without replacing the first sock) will be black?

Answer 1

Worst case scenario you would pull out 1 of each color (i.e., 3 pulls), then on the 4th pull you would get a match.

 

Probably of black sock first time is 12/26 or 6/13 (reduced).  Probability of pulling a sock the second time is 11/25.  Multiply these fractions together to get your probability.