Question
A box contains 2 blue, 3 black and 5 orange balls. In
how many ways can 3 balls be drawn from the box, if at least 1 black ball is to be included in the draw?Solution
We may have (1 black and 2 non black) or (2 black and 1 non black) or (3 black). Required number of ways = (3C1 × 7C2) + (3C2 × 7C1) + (3C3) => (45 + 18 + 1) = 85
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