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Combinations... pick numbers

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Combinations... pick numbers

by topspin360 » Tue Jun 12, 2012 5:20 am
How would we solve the following problem using combinations?

shouldnt it be (3C2*3C1 + 3C1*3C2)/6C3 ?

Two sets are defined as follows:

X = (4,5,8)
Y = (-1,1,2)

If a number is taken from set at random and another number is taken from set at random, what is the probability that the sum of these numbers will be an even integer?
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by gmat_and_me » Tue Jun 12, 2012 5:49 am
I don't think I understood the problem correctly. I'm going
to assume that the question is asking for sum of number from
first set and number from the second set. If that indeed is
the case, then

total number of sums possible is 3 * 3 = 9
Out of which (count) only 4 sums result in an even outcome.
Hence the probability should be 4/9.

HTH
topspin360 wrote:How would we solve the following problem using combinations?

shouldnt it be (3C2*3C1 + 3C1*3C2)/6C3 ?

Two sets are defined as follows:

X = (4,5,8)
Y = (-1,1,2)

If a number is taken from set at random and another number is taken from set at random, what is the probability that the sum of these numbers will be an even integer?
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by gmatwar13 » Tue Jun 12, 2012 7:57 am
Try to take numbers instead 2/3 *1/3 + 1/3*2/3=4/9... where each fraction is probablity..
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