In an examination which had 200 questions, students score 4 marks for every correct answer and lose 1 mark for every wrong answer.

A student attempted all the 200 questions and scored 200 marks. The number of questions, student answered correctly in the examination, is:

80

The correct answer is Option (3) → 80

Let the number of correct answers = $x$
Then number of wrong answers = $200 – x$

Scoring rule:

• Correct answer → +4
• Wrong answer → −1

Total score = 200

$4x - 1(200 - x) = 200$

$4x - 200 + x = 200$

$5x - 200 = 200$

$5x = 400$

$x = 80$