Three unbiased dices are thrown, what is the probability of getting a sum of…
2023
Three unbiased dices are thrown, what is the probability of getting a sum of at least 11?
- A.
1/2
- B.
13/36
- C.
1/3
- D.
11/36
Attempted by 20 students.
Show answer & explanation
Correct answer: A
Three dice have 6 x 6 x 6 = 216 equally likely outcomes.
For three fair dice, the sum distribution is symmetric around 10.5, so the number of outcomes with sum at least 11 equals the number with sum at most 10.
Thus favorable outcomes = 216 / 2 = 108, and probability = 108 / 216 = 1/2.