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 Author: questioner [ Sun Jan 29, 2012 7:43 pm ] Post subject: GMAT Counting Methods If each digit in the set A = {1, 2, 3, 4, 5} is used exactly once, in how many ways can the 5 digits be arranged?A. 6B. 24C. 72D. 96E. 120(E) There are 5! = 120 possible arrangements of the five digits with no restrictions. Every time an item is selected, it is reduced from the pool. (5)(4)(3)(2)(1) = 120----------Remember the rule of combination.

 Author: Gennadiy [ Sun Jan 29, 2012 7:54 pm ] Post subject: Re: t.1, qt. 17: combinatorics, permutations. Quote:Remember the rule of combination.In this question we deal with permutations.A combination would be some subset of a given set (order does NOT matter). For example, selecting three numbers out of five.

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