Question

The average marks of 18 students is 45. The marks of three students were misread as 48, 31, 95, instead of 98, 71, 59. Find the correct average.
1. 40
2. 46
3. 48
4. 41
5. None

Answer 1

Correct Answer - Option 3 : 48

Given:

Average marks of 18 students = 45

Marks of 3 students were misread as 48, 31 and 95 instead of 98, 71 and 59

Formula used:

Total marks = Average × Number of students

Calculation:

Total marks = 18 × 45

⇒ 810

Correct total = 810 – [(48 + 31 + 95) + (98 + 71 + 59)]

⇒ 810 – 174 + 228

⇒ 864

Correct average = 864/18

⇒ 48

∴ The correct average is 48.