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Re: Probability problem [#permalink]
29 Dec 2007, 01:27
For which of the following values of X is the equation (X+4)!/X! = (X+1)! true ?
Is there any easier way to solve the problem apart from backsolving ?
all i can think of, besides backsolving, is watching the intersection of numbers -- since X! in the denominator removes the "edge" the left side has and forces intersection with the right. i'd love to hear someone else's take. what i've said here amounts to backsolving.