Difficulty: Easy
Correct Answer: One year older
Explanation:
Introduction / Context:
Chain simple differences to compare two people indirectly via a third person.
Given Data / Assumptions:
Concept / Approach:
Express C in terms of B and then compare B and C directly.
Step-by-Step Solution:
Verification / Alternative check:
Pick B = 10 ⇒ A = 7 ⇒ C = 9 ⇒ B is 1 year older than C, consistent.
Why Other Options Are Wrong:
Two years older/younger or one year younger contradict C = B − 1.
Common Pitfalls:
Reversing who is older due to sign mistakes in the differences.
Final Answer:
One year older.
Discussion & Comments