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A bag contains 7 green and 8 white balls. If two balls are drawn simultaneously, the probability that both are of the same colour is -.

Correct answer: D. 7/15

  • A. 8/15
  • B. 2/5
  • C. 3/5
  • D. 7/15

Explanation

Same-colour selections are two green or two white: C(7,2) + C(8,2) = 21 + 28 = 49. Out of C(15,2) = 105 total pairs, the probability is 49/105 = 7/15. The likely wrong choice is 3/5, which results from an incorrect count of same-colour pairs.

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