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Two balls are selected from a box containing 2 blue and 7 red balls. What is the probability that at least one ball is blue?

Options

  1. A2 9
  2. B7 9
  3. C5 12
  4. D7 12

Correct answer

D. 7 12

Step-by-step solution

aligned & P = ^2 C ₁ ^7 C ₁ ^9 C ₂ + ^2 C ₂ ^7 C ₀ ^9 C ₂ & = 2 7 36 + 1 7 36 = 14+7 36 = 7 12 aligned

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