Multiple choice

The average marks of 45 students is shown as 65. It includes a wrong entry of 84 marks instead of 48 marks. The correct average is:

  1. 65.8 marks

  2. 67.4 marks

  3. 62.6 marks

  4. 64.2 marks
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Total marks = 45 * 65 = 2925. The error is 84 - 48 = 36. Correct total = 2925 - 36 = 2889. Correct average = 2889 / 45 = 64.2.

AI explanation

The total sum of the marks originally calculated is 45 * 65 = 2925. The correct sum requires subtracting the wrong entry of 84 and adding the actual score of 48, leading to a correct sum of 2925 - 84 + 48 = 2889. Dividing this correct sum by the 45 students gives the correct average of 2889 / 45 = 64.2 marks.

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