CBSE Class 10 Mathematics Basic 2025: question 19
Set in the CBSE Class 10 board exam of 2025, paper 430/1/1, section A, question 19, for 1 mark. Try it first; the hints and our step-by-step solution are below.
Q19 · 1 mark · Assertion-reasonCompetency-basedReal Numbers
Assertion (A): For any two natural numbers a and b, the HCF of a and b is a factor of the LCM of a and b.
Reason (R): HCF of any two natural numbers divides both the numbers.
Codes: (A) Both A and R are true and R is the correct explanation of A. (B) Both A and R are true, but R is not the correct explanation of A. (C) A is true, but R is false. (D) A is false, but R is true.
- (A)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- (B)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
- (C)Assertion (A) is true, but Reason (R) is false.
- (D)Assertion (A) is false, but Reason (R) is true.
Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 430/1/1.
Hints
Open one hint at a time and try again before the next.
Hint 1
Does the HCF divide ?
Hint 2
Does divide the LCM?
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.
R is true: the HCF divides both and .
- 1 mark
Since the HCF divides , and divides the LCM, the HCF divides the LCM. So A is true, and R is the correct explanation of A. The answer is option (A).
Answer: Option (A)
Where the marks are
- Both statements true and R explains A (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
More questions from Real Numbers
- 2025 board paper, set 430/2/1 (Basic), Q26(b) · 3 marksState the 'Fundamental Theorem of Arithmetic' and use it to find LCM of 36 and 54.
- 2025 board paper, set 430/5/1 (Basic), Q29 · 3 marksThe traffic lights at three different road crossings change after every 45 seconds, 75 seconds and 60 seconds …
- 2025 board paper, set 430/6/1 (Basic), Q25 · 2 marksUsing prime factorisation, find the HCF of 180, 140 and 210.
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.