The probability that the sum is 7 when you roll two dice is 1/6; the probability that the sum is 11 is 1/18. Suppose you play a game where you win if the sum is 7 or 11. What is the probability that you win?
A) 2/6
B) 2/18
C) 7/6
D) 2/9
E) 2/24

Question

Quizplus · Accepted Answer

The probability of winning is the sum of the probabilities of rolling a sum of 7 and a sum of 11.

P(win) = P(sum=7) + P(sum=11)

P(win) = 1/6 + 1/18

P(win) = 4/18

P(win) = 2/9

Therefore, the answer is D.

The Probability That the Sum Is 7 When You Roll