Question

The mean marks of 100 students were found to be 40. Later on, it was discovered that a score of 53 was misread as 83. Then, the correct mean will be:

• A. 37.5
• B. 35.6
• C. 39.7
• D. 38.7

Answer 1

The correct option is C 39.7

$\because$ Mean =40 [given]
and number of students = 100
$\therefore$ Total number of marks $=40\times 100$
$=4000$
The correct sum of observations
$=4000+53-83=4000-30=3970$
$\therefore$ Correct mean $=\frac{3970}{100}$
$=39.7$.