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Class 12 Probability · Short Answer2 Marksbinomial_distribution

Class 12 Maths · Probability · Short Answer #43

Draw four cards independently with replacement from a 52-card deck. Find P(at least three diamonds).

✅ Step-by-Step Solution

Final Answer: 13/256
  1. Each draw is a diamond with probability 13/52=1/4. Thus X, the diamond count, has binomial distribution with n=4,p=1/4.
  2. P(X≥3)=C(4,3)(1/4)³(3/4)+(1/4)⁴=12/256+1/256.
  3. Therefore P(at least three diamonds)=13/256.

📋 CBSE Stepwise Marking Scheme

  • [0.5 marks] Each draw is a diamond with probability 13/52=1/4. Thus X, the diamond count, has binomial distribution with n=4,p=1/4.
  • [1 mark] P(X≥3)=C(4,3)(1/4)³(3/4)+(1/4)⁴=12/256+1/256.
  • [0.5 marks] Therefore P(at least three diamonds)=13/256.

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