Question

The average marks of 50 students in an examination was 60. It was later found that the marks of one student had been wrongly entered as 36 instead of 63. The correct average is?
1. 59.54
2. 61.54
3. 60.54
4. 60.36

Answer 1

Correct Answer - Option 3 : 60.54

Given:

Average of 50 students = 60

Marks of one student had been wrongly written as 36 instead of 63

Formula used:

Sum of observations = Average × Number of observations

Calculation:

Total marks of all students = 50 × 60 = 3000

But one student’s marked wrongly entered 36 instead of 63

So exact total marks of all students = 3000 – 36 + 63 = 3027

Correct average of all the students = 3027/50 = 60.54

∴ The correct average is 60.54