Question

Two dice are thrown simultaneously. The probability of obtaining a total score of 5 is

विकल्प

•  1/18

•  1/12

•  1/9

• none of these

   

Answer 1

1/9

When two dice are thrown, there are (6 × 6) = 36 outcomes.
The set of all these outcomes is the sample space given by
S = (1, 1) , (1, 2), (1, 3), (1, 4), (1, 5), (1, 6)
      (2, 1) , (2, 2), (2, 3), (2, 4), (2, 5), (2, 6)
      (3, 1) , (3, 2), (3, 3), (3, 4), (3, 5), (3, 6)
      (4, 1) , (4, 2), (4, 3), (4, 4), (4, 5), (4, 6)
      (5, 1) , (5, 2), (5, 3), (5, 4), (5, 5), (5, 6)
      (6, 1) , (6, 2), (6, 3), (6, 4), (6, 5), (6, 6)
i.e. n(S) = 36
Let E be the event of getting a total score of 5.
Then E = {(1, 4), (2, 3), (3, 2), (4, 1)}
∴ n(E) = 4
Hence, required probability = \[\frac{n\left( E \right)}{n\left( S \right)} = \frac{4}{36} = \frac{1}{9}\]