Students in a hostel — Caselets Aptitude Question
Students in a hostel: A hostel houses 450 students. 60% are undergraduates and the rest postgraduates. Answer and worked solution on CodeKairo.
- Topic: Caselets
- Section: Data Interpretation
- Difficulty: Medium
- Time target: 75 seconds
Question
A hostel houses 450 students. 60% are undergraduates and the rest postgraduates. Two-fifths of the undergraduates are women.
How many undergraduate women are there?
Options
- 96
- 108
- 120
- 135
Show the answer and the worked solution
Correct answer: B. 108
Worked solution
- Undergraduates = 60% of 450 = 270.
- Women among them = (2/5) × 270 = 108.
Answer: 108.
The idea
Apply each fraction to its own base in sequence. Taking two-fifths of the full 450 would give 180 and is wrong.
Shortcut. Multiply the fractions first: 60% × 2/5 = 3/5 × 2/5 = 6/25 = 24%, and 24% of 450 is 108.
Common trap. 135 — halving the 270 undergraduates instead of taking two-fifths of them.