Arithmetic Ability
Permutations and Combinations

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Q.

A box contains 2 white balls, 3 black balls and 4 red balls. In how many ways can 3 balls be drawn from the box, if at least one black ball is to be included in the draw?

View Answer

Correct choice: B

Explanation:

We may have(1 black and 2 non-black) or (2 black and 1 non-black) or (3 black). Required number of ways=(3C1*6C2)+(3C2*6C1)+3C3 = (45 + 18 + 1) =64
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