Difficulty: Easy
Correct Answer: 47
Explanation:
Introduction / Context:
Here you must recognize 103823 as a perfect cube and identify its cube root. This is a standard indices skill used in number theory and quick arithmetic estimation.
Given Data / Assumptions:
Concept / Approach:
Estimate by bracketing with known cubes. Compute 46^3 and 47^3 (or 48^3) mentally or via incremental methods to see which equals 103823 exactly.
Step-by-Step Solution:
Verification / Alternative check:
Use (n+1)^3 − n^3 = 3n^2 + 3n + 1. From 46^3 = 97,336, add 3*46^2 + 3*46 + 1 = 3*2116 + 138 + 1 = 635 *? Wait carefully: 3*2116=6348; 6348+138+1=6487; 97336+6487=103,823, confirming 47^3.
Why Other Options Are Wrong:
Common Pitfalls:
Mixing up 47^2 (2209) with 47^3, or estimating too loosely without checking parity and growth between consecutive cubes.
Final Answer:
Discussion & Comments