How many ways of arranging five white stones and three black stones in one row are there?
Answer
56 ways
Solution
It is the same as considering how to put three black stones into the eight boxes arranged.
It becomes the way of choosing which chooses three boxes from eight boxes for putting three black stones in.
It is 8 × 7 × 6 / 3 × 2 × 1 = 56 ways.
