(a) While travelling abroad, I bought 7 identical bags of candy for 3 friends. How many ways can I distribute the candy to my 3 friends, so that each friend gets at least one bag of candy?
This is similar to distributing 7 identical balls into 3 distinct boxes with the restriction that each box must contain at least 1 ball
The number of ways is given by
C (7-1, 3 - 1) = C ( 6,2) = 15 ways
