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Combination incorrect mgmat

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Combination incorrect mgmat

by Jinglander » Fri Sep 24, 2010 5:11 pm
Ok here is a problem from mgmat that I don't agree with the answer. Please advise

Amy and Adam are making boxes of truffles for as wedding favors. They have an unlimited supply of 5 different types of truffles. If each box holds 2 truffles of different types how many different boxes can they make.

The book says it's 5!/3!2! but this seems wrong since there is a unlimited supply. Instead I would think u have 5 choices for the first and 4 for the second hense 20
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by diebeatsthegmat » Fri Sep 24, 2010 5:58 pm
Jinglander wrote:Ok here is a problem from mgmat that I don't agree with the answer. Please advise

Amy and Adam are making boxes of truffles for as wedding favors. They have an unlimited supply of 5 different types of truffles. If each box holds 2 truffles of different types how many different boxes can they make.

The book says it's 5!/3!2! but this seems wrong since there is a unlimited supply. Instead I would think u have 5 choices for the first and 4 for the second hense 20
why dont you list the number of flowers you can take? then you can understand the answer
ABCDE is 5 kinds of flowers. select 2 different flowers
AB, AC, AD,AE
BC,BD,BE
CD,CE,
DE thus only 10 choices.
when you add 5*4 it means you took the choice twice
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by Jinglander » Fri Sep 24, 2010 6:49 pm
Can I have a more in depth answer please
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