CBSE Class 10 Mathematics Standard 2025: question 18
Set in the CBSE Class 10 board exam of 2025, paper 30/2/1, section A, question 18, for 1 mark. Try it first; the hints and our step-by-step solution are below.
Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 30/2/1.
Hints
Open one hint at a time and try again before the next.
Hint 1
Write each number as a product of primes.
Hint 2
The HCF is the product of the smallest powers of the common primes.
Step-by-step solution
Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.
- ½ mark
, , .
- ½ mark
Common primes with their lowest powers: . So HCF . Option (D).
Answer: 10, option (D)
Where the marks are
- Prime factorises all three numbers and takes the lowest common powers to get 10, option (D) (1 mark)
Revise the chapter
- Chapter: Real Numbers (notes, formulas, where marks are lost and every past question)
- Topic: HCF and LCM by Prime Factorisation
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The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.