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by rish » Thu Aug 06, 2009 3:50 pm
How many different signals can be transmitted by hoisting 3 red, 4 yellow and 2 blue flags on a pole, assuming that in transmitting a signal all nine flags are to be used?
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by adssaini » Thu Aug 06, 2009 4:45 pm
is it 24 ?
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Re: Flags

by tohellandback » Thu Aug 06, 2009 6:12 pm
rish wrote:How many different signals can be transmitted by hoisting 3 red, 4 yellow and 2 blue flags on a pole, assuming that in transmitting a signal all nine flags are to be used?
9! / 3!4!2!
The powers of two are bloody impolite!!
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by sonaligmat » Fri Aug 07, 2009 7:47 am
Could someone give a detailed solution for this one?

Thanks.
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by rish » Fri Aug 07, 2009 9:05 am
Ans is 1260. Please explain the solution in detail.
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by vittalgmat » Fri Aug 07, 2009 3:01 pm
rish wrote:Ans is 1260. Please explain the solution in detail.
This problem is similar to a class of problems of the type below
https://www.beatthegmat.com/word-combina ... tml#144946

Here we have totally 9 flags. If all were different, then we will have 9! different permutations. But, we have reptitions. So we have to remove the the repeated permutations (all 4 red flags are indistinguishable from each other.).
So the formula now becomes.
Total items ! / repeated items !

applying this we get
9!/(4! *3! * 2!).

ie = 1260.


Ht helps
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