एक कक्षा में, 60% विद्यार्थी भारत से हैं और विद्यार्थियों का 50% लड़कियाँ हैं । यदि भारतीय विद्यार्थियों में 30% लड़कियाँ हैं, तो विदेशी विद्यार्थियों में कितने प्रतिशत लड़के हैं ?
Read this question in English
In a class, 60% of students are from India and 50% of the students are girls. If 30% of the Indian students are girls, then what percentage of foreign students are boys?
(a) 45% · (b) 40% · (c) 30% · (d) 20%
उत्तर और व्याख्या · explanation in English
Answer: (d) 20%
Take 100 students: 60 Indian and 40 foreign, with 50 girls. Indian girls are 18, so foreign girls are 32 and foreign boys only 8 — that is 8 out of 40 foreign students, or 20%.
- Take 100 students: 60 Indian, 40 foreign; 50 girls in all.
- Indian girls = 30% of 60 = 18.
- Foreign girls = 50 − 18 = 32, so foreign boys = 40 − 32 = 8.
- Share of boys among foreign students = 8/40 = 20%.
- Check: boys = 50; Indian boys 60 − 18 = 42 plus foreign boys 8 = 50.
Remember · Assume a total of 100 and fill a 2 × 2 table; then divide by the base the question names (here, foreign students).
Question and answer: UPSC's official GS Paper II (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·