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A box contains 6 blue, 4… (Class 10 Maths Basic 2025, Q30)

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MathsCBSE Class 10 · Basic · Board exam 2025, set 430/3/1 · 3 marks · Short answer

CBSE Class 10 Mathematics Basic 2025: question 30

Set in the CBSE Class 10 board exam of 2025, paper 430/3/1, section C, question 30, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q30 · 3 marks · Short answerProbability

A box contains 6 blue, 4 white and 8 red marbles. A marble is drawn at random from this box. Find the probability that the marble so drawn is:

  1. (i)

    white

    1 mark
  2. (ii)

    white or red

    1 mark
  3. (iii)

    not red

    1 mark

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 430/3/1.

Hints

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

Hint 1

First find the total number of marbles in the box.

Hint 2

For 'not red', count the blue and white marbles together, or use 1 − P(red).

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. Total number of marbles , so there are 18 equally likely outcomes.

    (i) P(white)

    1 mark

  2. (ii) Favourable outcomes . P(white or red)

    1 mark

  3. (iii) Non-red marbles . P(not red)

    1 mark

Answer: (i) 2/9; (ii) 2/3; (iii) 5/9

Where the marks are

  • (i) P(white) = 4/18 = 2/9 (1 mark)
  • (ii) P(white or red) = 12/18 = 2/3 (1 mark)
  • (iii) P(not red) = 10/18 = 5/9 (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 paper2025 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.