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?  Select: A) 8 B) 9 C) 10 D) 11 E) 12
Let the number of papers be x. Then,   63x + 20 + 2 = 65x   = 2x = 22   = x = 11.   ANSWER:11
<result>D</result>
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?