There are 3 defective pieces and 12 non-defective pieces. Number of ways to receive exactly 2 defective pieces and 3 non-defective pieces: 3C2*12C3 Number of ways to receive exactly 3 defective pieces and 2 nondefective pieces: 3C3*12C2 Answer 3C2*12C3 + 3C3*12C2 Edwin