Multiple choice

The average marks of 28 students in an examination was 63. It was later found that the marks of two students had been wrongly entered as 72 and 54 instead of 52 and 46 . The correct average is:

  1. $62$
  2. $57$
  3. $64$
  4. $72$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Original total = 28 × 63 = 1764. The wrong entries were 72 and 54 (sum = 126). Correct entries are 52 and 46 (sum = 98). The total should decrease by 126 - 98 = 28. Correct total = 1764 - 28 = 1736. Correct average = 1736/28 = 62.

Keep practicing — related questions