Problem:
A fair standard six-sided die is tossed three times. Given that the sum of the first two tosses equals the third, what is the probability that at least one "" is tossed?
Answer Choices:
A.
B.
C.
D.
E.
Solution:
There are ways in which the third outcome is the sum of the first two outcomes.
Since the three tosses are independent, all of the possible outcomes are equally likely. At least one "" appears in exactly eight of these outcomes, so the required probability is .