A cooler contains 11 cans of soda; 5 colas, 5 orange, and 1 cherry. Two cans are selected at random without replacement. Find the probability that at least one can is cola.
Chance that the first can chosen is cherry is 1/11. Chance that the first can chosen is not cherry and the second can chosen is cherry is (10/11)(1/10) = 1/11. So the required probability is 1/11 + 1/11 = 2/11.