Difficulty: Medium
Correct Answer: 38 years
Explanation:
Introduction / Context:
This number puzzle blends consecutive integers with perfect squares and perfect cubes. We are told Nitin’s current age sits exactly between a square (last year) and a cube (next year). We must deduce his present age and then the waiting time until his age becomes a cube again.
Given Data / Assumptions:
Concept / Approach:
If current age is n, then n − 1 is a perfect square and n + 1 is a perfect cube. Search small squares and cubes that differ by 2. This is rare; we test candidates around typical small square–cube values.
Step-by-Step Solution:
Consider square 25 (5^2) and cube 27 (3^3): they are exactly 2 apart.Thus n − 1 = 25 and n + 1 = 27 → n = 26.Current age = 26. Last year 25 (a square), next year 27 (a cube) meets the conditions.Next time Nitin’s age is a cube: the next cube after 27 is 64 (4^3).Waiting time = 64 − 26 = 38 years.
Verification / Alternative check:
Check immediate neighbors of other small squares or cubes (e.g., 16 and 27; 36 and 27): only 25 and 27 straddle an integer. So 26 is unique in this range.
Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:
38 years
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