Selecting two students — Probability Aptitude Question
Selecting two students: From 4 boys and 6 girls, two students are chosen at random. What is the probability that… Answer and worked solution on CodeKairo.
- Topic: Probability
- Section: Quantitative Aptitude
- Difficulty: Medium
- Time target: 75 seconds
Question
From 4 boys and 6 girls, two students are chosen at random. What is the probability that both are girls?
Options
- 1/3
- 2/5
- 3/5
- 5/9
Show the answer and the worked solution
Correct answer: A. 1/3
Worked solution
- Both girls: C(6,2) = 15.
- Total: C(10,2) = 45.
- Probability = 15/45 = 1/3.
Answer: 1/3.
The idea
Reduce the fraction fully — papers list the reduced form, and 15/45 would not appear among the options.
Shortcut. Draw in order: 6/10 × 5/9 = 30/90 = 1/3.
Common trap. "3/5" — using 6/10, the chance for a single pick, and forgetting that the second student must also be a girl.