In a certain examination, the average marks of an examinee is 64 per paper. if he had obtained 18 more marks for his Mathematics paper and 4 more marks for his English paper, his average per paper would have been 66. How many papers were there in the examination?
Correct Answer: 11
Explanation:
Let the number of papers = x.
According to the question,
64x + 18 + 4 = 66x
∴ 2x = 22
∴ x = 22/2 = 11