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#1 2006-11-27 12:18:34

ketildre
Member
Registered: 2006-11-27
Posts: 2

probability

If 4 different balls are placed randomly in 3 different boxes, what is the probability that non of the boxes are empty. Assume there is enough room in each box for 4 balls???

Anybody got a clue?

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#2 2006-11-27 16:29:11

pi man
Member
Registered: 2006-07-06
Posts: 251

Re: probability

The 3 digits numbers below represent the way the balls could end up in the boxes.  For example, 0 in the first box, 0 in the second box, 4 in the 3rd box.

004, 013, 022, 031, 040, 103, 112, 121, 130, 202, 211, 220, 301, 310, 400

Since each ball is placed randomly, each of the above possibilities are equally likely.  Only 3 of the 15 possible outcomes have at least 1 ball in all 3 boxes.  Thats 20%.

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