After the recent paper of JEE-MAIN 2015, a lot of people have been arguing with me about a question that was present in the paper. Before we look into the problem, first, let me give you another simple problem:
1.1 Two different coins are tossed simultaneously, find the probability that both show heads.
1.2 Two identical coins are tossed simultaneously, find the probability that both show heads.
Obviously, the answer to 1.1 is which is evident as we have one favorable case in the sample set .
Continuing on similar lines, people argue that the answer to 1.2 is as the sample set contains only : and we have one favorable case.(but this reasoning is incorrect. Infact the answer is still 0.25)
We now come to the actual problem:
2.If identical balls are to be placed in identical boxes, then the probability that one of the boxes contains exactly balls is
I'm not giving the answer or the method to do this problem as I want the reader to try it on their own before joining the discussion. The reader is advised to think about given problems before looking at the comments below.
Please do help me solve this! Thanks!