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प्रश्न
A box contains 2 white balls, 3 black balls and 4 red balls. The number of ways three balls be drawn from the box if at least one black ball is to be included in the draw is ______.
उत्तर
A box contains 2 white balls, 3 black balls and 4 red balls. The number of ways three balls be drawn from the box if at least one black ball is to be included in the draw is 64.
Explanation:
We have 2 white, 3 black and 4 red balls
It is given that atleast 1 black ball is to be included.
∴ Required number of ways = 3C1 × 6C2 + 3C2 × 6C1 + 3C3
= 3 × 15 + 3 × 6 + 1
= 45 + 18 + 1
= 64
Hence, the value of the filler is 64.
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