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From the data 1, 4, 7, 9, 16… (Class 10 Maths 2024, Q8)

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MathsCBSE Class 10 · Standard · Board exam 2024, set 30/1/1 · 1 mark · MCQ

CBSE Class 10 Mathematics Standard 2024: question 8

Set in the CBSE Class 10 board exam of 2024, paper 30/1/1, section A, question 8, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q8 · 1 mark · MCQProbability

From the data 1, 4, 7, 9, 16, 21, 25, if all the even numbers are removed, then the probability of getting at random a prime number from the remaining is:

  1. (A)
  2. (B)
  3. (C)
  4. (D)

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 30/1/1.

Hints

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

Hint 1

List what is left after removing the even numbers.

Hint 2

Remember that 1 is not a prime number.

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. Remove the even numbers 4 and 16. The remaining data are 1, 7, 9, 21, 25, which is 5 numbers.

  2. The only prime among them is 7 (1 is not prime; 9, 21 and 25 are composite). So . The answer is option (B).

    1 mark

Answer: , option (B)

Where the marks are

  • Identifies the 5 remaining numbers with one prime, giving , option (B) (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Probability, one at a time, marked against the answer key and marking points.Back to the full paper2024 board paper, set 30/1/1 (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.