Difficulty: Medium
Correct Answer: 11/36
Explanation:
Introduction / Context:We are asked for the probability that, in a single toss of two fair dice, the pair of outcomes has one value that is a multiple of 2 and the other value that is a multiple of 3. Order does not matter, so pairs like (6,6) should be counted once overall, not twice.
Given Data / Assumptions:
Concept / Approach:Use inclusion–exclusion over the two ordered scenarios: (Die1 multiple of 2 & Die2 multiple of 3) OR (Die1 multiple of 3 & Die2 multiple of 2). Subtract the overlap where both dice show a common multiple of 2 and 3, namely 6.
Step-by-Step Solution:
P(Die1 mult 2, Die2 mult 3) = (3/6)(2/6) = 1/6.P(Die1 mult 3, Die2 mult 2) = (2/6)(3/6) = 1/6.Overlap P(Die1=6, Die2=6) = (1/6)*(1/6) = 1/36.Total = 1/6 + 1/6 − 1/36 = 12/36 − 1/36 = 11/36.Verification / Alternative check:Counting favorable ordered pairs directly: {2,3},{2,6},{4,3},{4,6},{6,3},{6,6} and the symmetric ones where roles swap; careful de-duplication yields 11 favorable outcomes out of 36.
Why Other Options Are Wrong:1/3 double-counts (6,6) without inclusion–exclusion. 1/4 and 7/26 come from ad-hoc approximations, not exact counting.
Common Pitfalls:Double-counting (6,6) because it satisfies both role assignments; forgetting that order is part of the 36 equally likely ordered outcomes.
Final Answer:11/36
Discussion & Comments