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There are three bells… (Class 10 Maths SQP 2026-27, Q21B)

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MathsCBSE Class 10 · Standard · Sample paper, session 2026-27 · 2 marks · Very short answer

CBSE Class 10 Mathematics Standard sample paper 2026-27: question 21(B)

From the official CBSE sample question paper for 2026-27, section B, question 21(B), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q21(B) · 2 marks · Very short answerCompetency-basedReal Numbers

There are three bells placed at different swings in a park, which toll at intervals of 5, 6 and 8 minutes, respectively. They all toll together when the park opens for the visitors at 10:00 a.m. How many more times do they all toll together till the park is closed at 7:00 p.m.?

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2026-27.

Hints

Open one hint at a time and try again before the next.

Hint 1

The bells toll together after a common multiple of their intervals.

Hint 2

Find the LCM, then count the times from 10 a.m. to 7 p.m.

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.

  1. , , , so . The bells toll together every 120 minutes, that is every 2 hours.

    1 mark

  2. Starting at 10:00 a.m., they toll together again at 12:00 noon, 2:00 p.m., 4:00 p.m. and 6:00 p.m. The next time would be 8:00 p.m., which is after closing. So they toll together 4 more times.

    1 mark

Answer: 4 more times

Where the marks are

  • LCM of 5, 6, 8 = 120 min = 2 hours (1 mark)
  • Lists the times up to 7 p.m. and concludes 4 more times (1 mark)

Revise the chapter

  • Chapter: Real Numbers (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Real Numbers, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2026-27 (Standard): every question, by section.

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.