Q. In an examination, the average of marks was found to be 50. For deducting marks for computational errors, the marks of 100 candidates had to be changed from 90 to 60 each and so the average of marks came down to 45. The total number of candidates, who appeared at the examination, was
✅ Correct Answer: (A)
600
Explanation: Here , The average of marks was found to be 50
Let total number of candidates be n.
According to question,
∴ 50n – 30 × 100 = 45n
⇒ 50n - 45n = 30 × 100
⇒ 5n = 3000
⇒ n = 3000 ÷ 5 = 600
Explanation by: Vaibhav Shukla
Here , The average of marks was found to be 50
Let total number of candidates be n.
According to question,
∴ 50n – 30 × 100 = 45n
⇒ 50n - 45n = 30 × 100
⇒ 5n = 3000
⇒ n = 3000 ÷ 5 = 600
Let total number of candidates be n.
According to question,
∴ 50n – 30 × 100 = 45n
⇒ 50n - 45n = 30 × 100
⇒ 5n = 3000
⇒ n = 3000 ÷ 5 = 600