In an examination, a student scores 4 marks for every correct answer and losses 1 mark for every wrong answer. A student attempted all 200 questions and scored 500 marks. What is the number of questions, he answered correctly?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 140.
Let the number of correct answers = C and the number of wrong answers = W
C + W = 200 .....(1)
4C - W = 500 .....(2)
Adding (1) and (2), we get
5C = 700
⇒ C = 140