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 150 marks, the no of questions he attempts correctly is :	Choose one.
A) 35	B) 38	C) 40	D) 42	E) 44
Explanation:   Let the number of correct answers be X.   Number of incorrect answers = (60 – X).   4x – (60 – x) = 150   =&gt; 5x = 210   =&gt; x = 42   Answer: 42
<result>D</result>
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 150 marks, the no of questions he attempts correctly is :