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Permutation - Quant/Math - CAT 2013
Question 4 the day:
May 6, 2003
The question for the day is from the topic of Permutation.
- In how many ways can 4 boys and 7 girls be arranged in a row, so that all the boys are together?
| (1) |
4!.7! |
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(2) |
8! |
| (3) |
8!.4! |
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(4) |
7! |
Correct Answer - (3)
Solution:
We consider 4 boys as one unit, so that we have to arrange 8 units (1 unit of boys + 7 unit of boys). We can arrange this in 8P8 = 8! ways. The 4 boys can themselves be arranged in 4! Ways. Thus the required number of ways = 8!.4!
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