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| Permutation (from score 800) |
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Dan Bernstein
MGMAT STAFF
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Ruben, one key to correctly answering a combinatorics problem is to identify the problem type as an arrangement (permutation) or a grouping (combination). This is simply a relatively straightforward arrangement problem.
The first contestant to win a prize has 6 potential outcomes. As this person must win one prize (no matter which prize it is), the second contestant has 5 potential outcomes. By the same logic, the third contestant has 4 potential outcomes, and the fourth contestant has 3 potential outcomes. The total number of arrangements (permutations) is simply the product of the number of outcomes for each contestant: 6*5*4*3 = 360. The correct answer is E. ps. You might see other notation or approaches concerning these types of combinatorics problems (such as 6P4 or 6!/2!) but the underlying logic is identical. Hope that helps. -dan |
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| Contestants can win more than one prize each? |
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mpavey
Guest
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The way I read this question, it is ambiguous. It sounds like it would be possible for each contestant to win more than one prize. That would mean that contestant 1 could walk away with no prizes, one prize, two prizes, ... or even all six prizes.
How would we calculate the number of possible outcomes in this case? |
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Stacey Koprince
MGMAT STAFF
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"Each contestant can win one prize" is not ambiguous. Each can win one prize, period.
You won't see a question of the type you describe on the test because it would take longer than 2 minutes to calculate (without a calculator). |
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| Permutation |
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