Vaibhav Shukla • 4.53K Points
Extraordinary Math

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

(A) 600
(B) 300
(C) 200
(D) 150

Correct Answer - Option(A)
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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

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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

Explanation by: Vaibhav Shukla

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