Aptitude Discussion

Q. |
When two dice are thrown simultaneously, what is the probability that the sum of the two numbers that turn up is less than 11? |

✖ A. |
5/6 |

✔ B. |
11/12 |

✖ C. |
1/6 |

✖ D. |
1/12 |

**Solution:**

Option(**B**) is correct

Instead of finding the probability of this event directly, we will find the probability of the non-occurrence of this event and subtract it from 1 to get the required probability.

Combination whose sum of 12 is (6,6)

Combinations whose sum of 11 is (5,6), (6,5).

Therefore, there are totally 3 occurrences out of 36 occurrences that satisfy the given condition.

Probability whose sum of two numbers is greater than or equal to 11:

\(=\dfrac{3}{36}=\dfrac{1}{12}\)

Hence probability whose sum of two numbers is lesser than 11:

\(=1-\dfrac{1}{12}\)

\(=\dfrac{11}{12}\)