In an examination, a student scores 3 marks for every correct answer and loses 1 mark for every wrong answer. If he attempts all 30 questions and secures 130 marks, the no of questions he attempts correctly is :  Pick one: A) 35 B) 40 C) 90 D) 88 E) 37

Rationale: let the number of correct answers be x . number of incorrect answers = ( 60 – x ) . 3 x – ( 30 – x ) = 130 = > 4 x = 160 = > x = 40 answer : b
Answer: B