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GMATPrep Probability Q

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by agps » Fri Aug 31, 2007 1:16 am
total possibilities = 27 (3*3*3 because he can ride any of the 3 cars each time)
favorable possibilities = 6 (1-2-3, 1-3-2, 2-1-3, 2-3-1, 3-1-2, 3-2-1)

6/27 = 2/9

Answer C
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by kevincanspain » Fri Aug 31, 2007 2:17 pm
This is the probability that the second ride is not in the same car as the first multiplied by the probability that the third ride is in the car not previously ridden in given that the first and second rides were in different cars.

2/3 * 1/3 =2/9
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