Arrangements

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Arrangements

by yellowho » Tue Mar 01, 2011 9:09 pm
A man has 7 different pets and wishes to photograph 3 at a time. How many different arrangements are possible?

Does "arrangement" automatically signals that order matters? What's the difference between arrangements and "ways."

OA here is [spoiler]210[/spoiler]
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by Anurag@Gurome » Tue Mar 01, 2011 9:35 pm
yellowho wrote:A man has 7 different pets and wishes to photograph 3 at a time. How many different arrangements are possible?

Does "arrangement" automatically signals that order matters? What's the difference between arrangements and "ways."

OA here is 210
Arrangement refers to permutation (order matters) and ways refers to combination (order does not matter).
7P3 = 210
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by Night reader » Tue Mar 01, 2011 9:48 pm
@Anurag, in this specific problem, using the word "arrangement", what's the difference between selecting three pets ABC and CBA or BCA? They are all different pets just selected for photograph, and I think there's huge number of GMAT problems putting the word "arrangement" just to trick the possibility of light knowledge gained by test-takers on permutation and combination topics. Have not we need additional clues here to assume that order matters besides the use of word "arrangement"?
Anurag@Gurome wrote:
yellowho wrote:A man has 7 different pets and wishes to photograph 3 at a time. How many different arrangements are possible?

Does "arrangement" automatically signals that order matters? What's the difference between arrangements and "ways."

OA here is 210
Arrangement refers to permutation (order matters) and ways refers to combination (order does not matter).
7P3 = 210
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