A box contains 6 blue shirts, 7 yellow shirts and 9 pink shirts. In how many ways can 4 shirts be drawn from the box, if at least one blue shirt, one yellow shirt and one pink shirt is to be included in a draw?
Required number of ways = (6C2 ) × 7C1 × 9C1 => (15 × 7 × 9) + (6 × 21 × 9) + (6 × 7 × 36) => 945 + 1134 + 1512 = 3591
