Multiple choice

In an examination, a pupil's average marks were 63 per paper. If he would have obtained 20 more marks in Geography and 2 more marks in History, his average marks per paper would have been 65. How many papers were there in the examination?

  1. 7

  2. 8

  3. 10

  4. 11

  5. 15
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let n be the number of papers. Initial sum = 63n. New sum = 63n + 22. New average = (63n + 22)/n = 65. 63n + 22 = 65n, so 2n = 22, n = 11.

AI explanation

Let the number of papers be n. The total increase in marks across all papers is the difference between the desired total and the original total, expressed as 65n - 63n = 2n. This increase comes from the 20 extra marks in Geography and 2 extra marks in History, totaling 22 additional marks. Setting the equation 2n = 22 gives n = 11, meaning there were 11 papers.

Keep practicing — related questions