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Explain why (7 × 11 × 13… (Class 10 Maths Basic 2024, Q23b)

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MathsCBSE Class 10 · Basic · Board exam 2024, set 430/3/1 · 2 marks · Very short answer

CBSE Class 10 Mathematics Basic 2024: question 23(b)

Set in the CBSE Class 10 board exam of 2024, paper 430/3/1, section B, question 23(b), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q23(b) · 2 marks · Very short answerReal Numbers

Explain why is not a prime number.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 430/3/1.

Hints

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

Hint 1

Look for a factor common to both terms.

Hint 2

Take 11 common; a number with a factor other than 1 and itself is composite.

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. Taking 11 common:

    1 mark

  2. So the number has factors other than 1 and itself (for example 11 and 93). Hence it is a composite number, not a prime number.

    1 mark

Answer: It equals , so it has factors other than 1 and itself; hence it is composite, not prime.

Where the marks are

  • Writes the number as (1 mark)
  • Concludes it has more than two factors, so it is not prime (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Real Numbers, one at a time, marked against the answer key and marking points.Back to the full paper2024 board paper, set 430/3/1 (Basic): 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.