The total number of ways in which 5 balls of different colours can be distributed among 3 persons so that each person gets at least one ball is
- (A)75
- (B)150✓ Correct
- (C)210
- (D)243
Answer: (B)
Solution
We use the inclusion-exclusion principle. The total number of ways to distribute 5 distinct balls among 3 persons (without restriction) is . We subtract the cases where at least one person gets no ball: (one person gets nothing). We add back the cases where at least two persons get no ball: (two persons get nothing). By inclusion-exclusion: .
JEE Advanced · 2012 · 08 Apr 2012 · Paper 1 · Single correct option