Question

If 12 identical balls are to be placed in 3 identical boxes, then the probability that one of the booxes contain exactly 3 balls

Answer 1

Three balls can be placed in any one of the boxes in 3 ways. The remaining 9 balls can be placed in the remaining two identical boxes is in( 0,9),(1,8),(2,7),(3,6),(4,5) in 5 ways. Total number of ways distribution is 3*5=15