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Topic

LCM and HCF

Asked 2 times across 2 UPSC exams over 2 years (2021–2023), peaking in 2023.
2
PYQs
2
Exams
2
Years active
2021–2023
Span
2023
Peak
2/2
Answers
📅 Full chronological timeline →

Key insights

  • Most tested in EPFO — 1 of 2 PYQs
  • Most asked in 2023
  • Recurs across 2 years (2021–2023)

How it travelled across exams

First appearance in each exam — the same idea, reframed.
CISF 2021 EPFO 2023

How the concept evolved

121
123
Rising — more than half its appearances (2 of 2) are since 2016.

Sample questions

You've seen the pattern — here are a few of the actual PYQs.
EPFO2023
If x is the smallest natural number that is divisible by both 24 and 30, whereas y is the largest natural number that divides both 36 and 100, then what is the value of x − y?
  1. A 116 ✓
  2. B 124
  3. C 128
  4. D 132
✓ Correct answer: (A)
Quantitative Aptitude › Number System
CISF2021
If the LCM and HCF of two positive integers are 18 and 3 respectively, then what is the minimum possible value of their sum ?
  1. A 21
  2. B 15 ✓
  3. C 18
  4. D 16
✓ Correct answer: (B)
Quantitative Aptitude › Number System

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