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On a particular day… (Class 10 Maths SQP 2025-26, Q30)

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MathsCBSE Class 10 · Standard · Sample paper, session 2025-26 · 3 marks · Short answer

CBSE Class 10 Mathematics Standard sample paper 2025-26: question 30

From the official CBSE sample question paper for 2025-26, section C, question 30, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q30 · 3 marks · Short answerCompetency-basedProbability

On a particular day, Vidhi and Unnati couldn’t decide on who would get to drive the car. They had one coin each and flipped their coin exactly three times. The following was agreed upon:
1. If Vidhi gets two heads in a row, she would drive the car
2. If Unnati gets a head immediately followed by a tail, she would drive the car.
Who has greater probability to drive the car that day? Justify your answer.

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2025-26.

Hints

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

Hint 1

List all 8 outcomes of three coin flips.

Hint 2

For each girl, count the outcomes that contain her pattern (HH, or HT) in consecutive flips.

Hint 3

Compare the two probabilities.

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. Three flips of a coin give equally likely outcomes: HHH, HHT, HTH, HTT, THH, THT, TTH, TTT.

  2. Vidhi needs two heads in a row: HHH, HHT, THH, which is 3 outcomes.
    .

    1 mark

  3. Unnati needs a head immediately followed by a tail: HHT, HTH, HTT, THT, which is 4 outcomes.
    .

    1 mark

  4. Since , Unnati has the greater probability of driving the car that day.

    1 mark

Answer: Unnati (4/8 > 3/8)

Where the marks are

  • Finds P(Vidhi) = 3/8 with the favourable outcomes listed (1 mark)
  • Finds P(Unnati) = 4/8 with the favourable outcomes listed (1 mark)
  • Compares the two and concludes that Unnati is more likely to drive (1 mark)

Revise the chapter

  • Chapter: Probability (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Probability, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2025-26 (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.