csatmedium
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?
- A.12
- B.21
- C.43
- D.45
▶ Answer & Explanation
Correct answer: B. 21
Let 'n' be the number of students in the class. According to the problem, each student contributes 'n' rupees. Thus, the total contribution without any additional amount would be n*n = n^2 rupees. When an additional Rs. 2 is collected, the total collection becomes Rs. 443. This means n^2 + 2 = 443, which simplifies to n^2 = 441. Taking the square root of both sides, n = 21. Therefore, there are 21 students in the class.
Source: UPSC csat 2016