In an examination, a student scores 4 marks for every correct answer and loses 1 mark for every wrong answer. If he attempts all 80 questions and secures 120 marks, How many questions does he answer correctly?	Choose the correct choice from the following answers:
A) 20	B) 10	C) 30	D) 50	E) 40
Let the number of correct answers be x   Then, number of wrong answers = (80 - x)   4x – (80 - x) = 120   =&gt; 4x – 80 + x = 120   =&gt; 5x = 200   =&gt; x = 200/5= 
<gadget id="calculator">200/5</gadget>
<output>40</output>
40   i.e., he does 40 questions correctly   Answer is 40.
<result>E</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 80 questions and secures 120 marks, How many questions does he answer correctly?