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A dealer has a stock of 15 gold coins out of which 6 are counterfeits. A person randomly picks 4 of the 15 gold coins. What is the probability that all the coins picked will be counterfeits?

Options

  1. A1 91
  2. B4 91
  3. C6 91
  4. D15 91

Correct answer

A. 1 91

Step-by-step solution

Number of ways of picking 4 counterfeits gold coins out of 6 counterfeits coins = ^6 C₄ Number of ways of picking 4 coins out of 15 gold coins = ¹⁵ C₄ Required probability = ^6 C₄ ¹⁵ C₄ = 15 15 7 13 = 1 91 .

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