A king or a heart — Probability Aptitude Question
A king or a heart: One card is drawn from a standard pack of 52. What is the probability that it is a king or a… Answer and worked solution on CodeKairo.
- Topic: Probability
- Section: Quantitative Aptitude
- Difficulty: Easy
- Time target: 45 seconds
Question
One card is drawn from a standard pack of 52. What is the probability that it is a king or a heart?
Options
- 17/52
- 1/4
- 15/52
- 4/13
Show the answer and the worked solution
Correct answer: D. 4/13
Worked solution
- Favourable cards = 4 kings + 13 hearts − 1 (the king of hearts, counted twice) = 16.
- Probability = 16/52 = 4/13.
Answer: 4/13.
The idea
P(A or B) = P(A) + P(B) − P(A and B). Forgetting the overlap gives 17/52, which is offered as a trap.
Shortcut. Count the 13 hearts, then add only the 3 kings that are not hearts: 16/52 = 4/13.
Common trap. 17/52 — adding 4 kings and 13 hearts and counting the king of hearts twice; removing the overlap gives 16/52.