Colorful OddsProbability puzzles require you to weigh all the possibilities and pick the most likely outcome.
There are four colored balls in a hat: two red, one black and one blue. After pulling out two of them, you know that one of them is red, but you do not know which one. What is the probability that both balls are red?
Answer1 in 5. The only possible combinations are:
 red1, black
 red1, blue
 red1, red2
 red2, black
 red2, blue
 black, blue
Since you know that one of the balls is red, that eliminates possibility , which has no red. Therefore, because all the remaining possibilities are equally likely, the probability is 1/5.
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