In an examination, a pupil's average marks were 63 per paper. If he had obtained 20 more marks for his Geography paper and 2 more marks for his History paper, his average per paper would have been 65. How many papers were there in the examination ?
Correct Answer: 11
Explanation:
Let the number of papers be x. Then, 63x + 20 + 2 = 65x or 2x = 22 or x = 11.
