What is the probability of rolling an even number on a fair six-sided die?

• A. 1/3
• B. 1/2
• C. 2/3
• D. 1

Answer: (B)

Think of a fair six-sided die as having six equally likely outcomes: 1, 2, 3, 4, 5, and 6. An even roll can happen on 2, 4, or 6, which are three favorable outcomes. Since each outcome has probability 1/6, the chance of an even result is 3 × (1/6) = 1/2. So the probability is 1/2. This rules out the other options: two favorable outcomes would give 1/3, four favorable would give 2/3, and all six would be 1.