In an examination, a student scores 4 marks for every correct answer and loses 1 mark for every wrong answer. If he attempts all 60 questions and secures 120 marks, the no of questions he attempts correctly is :  Choose the correct choice
A) 35
B) 36
C) 40
D) 42
E) 44

Rationale: "explanation : let the number of correct answers be x . number of incorrect answers = ( 60 – x ) . 4 x – ( 60 – x ) = 120 = > 5 x = 180 = > x = 36 answer : b"
Answer: B