Two cards are drawn successively without replacement from a standard 52‑card deck. What is the probability that the second card is a king given that the first card drawn is a heart?
Answer
1/13
The correct answer is 1/13 — Thus the required probability is .
Step-by-step solution
- Identify the conditional probability to be found: .
- Consider the two possible cases for the first heart: it could be the king of hearts or any other heart.
- If the first card is the king of hearts (probability ), 3 kings remain among the 51 cards left. Probability of second being king in this case is .
- If the first card is not the king of hearts (probability ), 4 kings remain among the 51 cards left. Probability in this case is .
- Apply the law of total probability: .
- Thus the required probability is .
Common mistake: Assuming the number of kings remaining is always 4 without considering the king of hearts possibility
Concept tested: Conditional probability with dependent draws
Published · How this solution was prepared and checked
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