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Mathematics — Standard (041) — CBSE Class 10 board question

Q1. [1] § 1.4 Summary
If the product of two co-prime numbers is 553, then their HCF is :
  1. A $1$
  2. B $553$
  3. C $7$
  4. D $79$
Previously asked in CBSE board exam
2024 30/5/1 Q14
Generated by claude-sonnet-4-6 · 2026-06-15 10:29 · grounding rag
Model Answer

Answer: A) 1

Co-prime numbers have no common factor other than 1, so their HCF is always 1.

Explanation

By definition, co-prime (relatively prime) numbers have HCF = 1. The value of their product (553 = 7 × 79) is irrelevant to finding the HCF — it is always 1 for any pair of co-prime numbers. Examiners expect students to recall this property directly.

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Previous-year CBSE Grade 10 board exam questions, organised by subject and chapter, each with a model answer — free to read and print.