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NDA 2020 Maths · Mathematics · Probability · easy

Two fair dice are thrown together. The probability that the product of the numbers on them is 12 is

Single correct option

Two fair dice are thrown together. The probability that the product of the numbers on them is 1212 is
  1. A. 112\dfrac1{12}
  2. B. 536\dfrac5{36}
  3. C. 19\dfrac19
  4. D. 16\dfrac16
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Answer: (C) 19\dfrac19

Among the 3636 equally likely outcomes, the pairs with product 1212 are (2,6),(6,2),(3,4),(4,3)(2,6),(6,2),(3,4),(4,3): four outcomes. So the probability is 436=19\dfrac4{36}=\dfrac19. The value 112=336\dfrac1{12}=\dfrac3{36} counts only three pairs, since the ordered pairs (2,6)(2,6) and (6,2)(6,2) are distinct outcomes, and 536\dfrac5{36} is the chance of sum 88. List ordered pairs for two dice.
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Original question written in the NDA 2020 Maths pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake