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Three different numbers are selected at random from the first 15 natural numbers. What is the probability that the product of two of the numbers is equal to third number?

Options

  1. A1 91
  2. B2 455
  3. C1 65
  4. D6 455

Correct answer

D. 6 455

Step-by-step solution

aligned n( ~S ) & = ¹⁵ C ₃ 2 3 & =6 2 4 & =8 2 5 & =10 2 6 & =12 2 7 & =14 3 4 & =12 aligned n( E )=6 Required probability = 6 ¹⁵ C ₃ = 6 15 14 13 12! 12! 3 2 = 6 35 13 = 6 455

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