Anwesha's marks in a class text of Sanskrit were incorrectly entered as 99 instead of 66. If there are 55 students in the class, then what is the increment in the average marks of the class in Sanskrit because of this typing error?

Correct option is C

Given:

Anwesha's marks were incorrectly entered as 99 instead of 66.

There are 55 students in the class.

Formula Used:

Average = $$\frac{\text{Total sum of marks}}{\text{Number of students}}$$​

Solution:

Let the original sum of marks for all students be S. The average before the error was:

Original average =$$\frac{S}{55}$$​

Impact of the error: The marks of Anwesha were incorrectly entered as 99 instead of 66. So, the total sum of marks increased by:

99 - 66 = 33

New sum of marks: The new sum of marks becomes S + 33.

New average =$$\frac{S + 33}{55}$$​

The increment in the average is the difference between the new average and the original average:

Increment= $$\frac{S + 33}{55} - \frac{S}{55} = \frac{33}{55} = 0.6$$ 

Alternate Solution:

Change in average = $$\frac{99 - 66}{55} = \frac{33}{55}$$​ = 0.6