CBSE Class 10 Mathematics Standard 2026: question 31
Set in the CBSE Class 10 board exam of 2026, paper 30/4/1, section C, question 31, for 3 marks. Try it first; the hints and our step-by-step solution are below.
Q31 · 3 marks · Short answerReal Numbers
Find the greatest number less than 10,000 which is exactly divisible by 48, 60 and 65.
Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 30/4/1.
Hints
Open one hint at a time and try again before the next.
Hint 1
A number divisible by 48, 60 and 65 must be a multiple of their LCM.
Hint 2
Find the LCM, then find its largest multiple that is still less than 10,000.
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.
- 1½ marks
Prime factorisation: , , .
- 1 mark
LCM.
- ½ mark
Any number divisible by all three is a multiple of 3120: , but . So the required number is .
Answer: 9360
Where the marks are
- Correct prime factorisation of 48, 60 and 65 (1½ marks)
- LCM = 3120 (1 mark)
- Greatest multiple below 10,000 = 9360 (½ 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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