manpsingh87 wrote:In how many ways can 3 letters can be selected from 3 identical A's,3 identical B's,3 identical C's ?
A)15
B)10
C)27
D)25
E)20
All 3 letters the same:
AAA, BBB, CCC = 3 ways.
Two letters the same, the other different:
AAB, AAC = 2
BBA, BBC = 2
CCA, CCB = 2
2+2+2 = 6 ways.
All 3 letters different:
ABC = 1 way.
Total number of ways = 3+6+1 = 10 ways.
The correct answer is
B.
The solution above assumes that we want to count the number of different combinations that can be chosen.
The wording of the question is unclear.
Is AAC a different way of selecting the letters from CAA?
If so, then the solution would be 3*3*3 = 27 ways.
An actual GMAT question would use more precise wording.
Last edited by
GMATGuruNY on Fri Apr 01, 2011 9:48 am, edited 1 time in total.
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