In aid of charity, every student in a class contributes as many rupees as the number of students in that class. With the additional contribution of Rs. 2 by one student only, the total collection is Rs. 443. Then how many students are there in the class?
Answer & explanation
Answer: (b) 21
If there are n students, each gives Rs. n, so the collection is n². With the extra Rs. 2 it is 443, so n² = 441 and n = 21.
- n students each give Rs. n: total = n².
- n² + 2 = 443, so n² = 441 and n = 21.
- Check: 21 × 21 = 441; 441 + 2 = 443.
Remember · 'As many rupees as the number of people' makes the total a perfect square — look for the square near the figure.
Question and answer: UPSC's official GS Paper II (2016, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·