Difficulty: Easy
Correct Answer: 31 cm
Explanation:
Introduction / Context:
“Measuring exactly” multiple lengths using the greatest possible length is a Highest Common Factor (HCF) problem. Converting all measures to the same unit (centimeters) and computing the HCF yields the required maximum measuring length.
Given Data / Assumptions:
Concept / Approach:
Convert each to centimeters and compute their HCF. The HCF is the largest length that divides all three exactly with no remainder.
Step-by-Step Solution:
Verification / Alternative check:
Divide each: 403/31 = 13, 434/31 = 14, 465/31 = 15 — all integers.
Why Other Options Are Wrong:
28, 29, 32, and 27 do not divide all three lengths exactly (at least one will leave a remainder).
Common Pitfalls:
Forgetting to convert meters to centimeters consistently; attempting to take the HCF in mixed units leads to errors.
Final Answer:
31 cm
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