Question

A student’s marks were wrongly entered as 93 instead of 39. Due to that, the average marks for the class got increased by 1. Find the number of students in the class.

• A. 27
• B. 26
• C. 45
• D. 54

Answer 1

Answer:

D. 54

Solution:

Given:

Wrongly entered marks = 93 and Correct marks = 39

Difference in average = 1

Calculation:

The total increase in average marks due to the wrongly entered score. 

Total increase in marks = 93 - 39 = 54

The total increase in marks is also equal to the difference in the average times the number of students. We know that the average increased by 1.

Total increase in marks = Difference in average $\times$ No of students

⇒ 54 = 1 $\times$ No of students

No of students = $\frac{54}{1} = 54$

∴ The total number of students in the class is 54.