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A bag contains 40 tickets numbered from 1 to 40 . Two tickets are drawn from the bag without replacement. The probability that the 2 n d ticket is a perfect square given that the 1 s t ticket was a perfect square is

Options

  1. A1 6
  2. B5 39
  3. C3 20
  4. D1 8

Correct answer

B. 5 39

Step-by-step solution

A = 1 s t ticket drawn is a perfect square B = 2 n d ticket drawn is a perfect square P A = 6 40 ;   P A ∩ B = 6 C 2 40 C 2 = 6 × 5 40 × 39 P B A = P B ∩ A P A = 6 × 5 40 × 39 × 40 6 = 5 39

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