13but i think it should be 28c8
In how many ways can 20 identical balls be distributed among 9 children?
i want to make it clear:
*all 20 balls may not be distributed
*each of them may not get a ball
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7 Answers
62The reason is simple there are 20 balls and putting 9 dividers will divide the balls in 10 parts.. 1 part will not be distributed.. the other 9 will be given in order to the 9 children
62*all 20 balls may not be distributed
*each of them may not get a ball
If this second condition was not there..
that each ball may not be distributed.. u wud be right..
but we have to keep one part with ourselves :)
13I think it should be..........(29C9 - 1)
we should not take the case where no balls were distributed among the children.
62hmm.. may be .. but then these small things depend on the writer of the question (he needs to be a bit more specific at times :)
but i guess the essense of solving these problems is very imporatant..
in IIT u wiill never get vague questions ... so :)