A pupil's marks were wrongly entered as 85 instead of 33. Due to that the average marks for the class got increased by half. The number of pupils in the class is :
Choose the correct answer: A) 30 B) 104 C) 20 D) 25 E) 26

Rationale: "let there be x pupils in the class . total increase in marks = ( x * 1 / 2 ) = x / 2 . x / 2 = ( 85 - 33 ) = > x / 2 = 52 = > x = 104 . answer : b"
Answer: B