Difficulty: Easy
Correct Answer: 15 years
Explanation:
Introduction / Context:
Age chains are solved by stepping differences forward or backward. Here we link three people via fixed gaps and use one absolute age to anchor the rest.
Given Data / Assumptions:
Concept / Approach:
Express R and N in terms of A or vice versa, then compute.
Step-by-Step Solution:
1) From A = R + 5 and A = 17 ⇒ R = 12.2) From R = N − 3 ⇒ N = R + 3 = 15.
Verification / Alternative check:
Check gaps: A − R = 5 (17 − 12); N − R = 3 (15 − 12). All consistent.
Why Other Options Are Wrong:
They violate one of the fixed differences when back-checked.
Common Pitfalls:
Reversing “younger than” vs “older than.” Carefully track sign and direction.
Final Answer:
15 years
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