Question

In a competitive examination, there were 60 questions. The correct answer would carry 2 marks, and for incorrect answer 1 mark would be subtracted. Yashwant had attempted all the questions and he got total 90 marks. Then how many questions he got wrong?

Answer 1

Let the number of correct answers be x and the number of incorrect answers be y.
Total answers = Number of correct + number of incorrect =
x + y = 60............ (I)
Total marks obtained = 90
2x - y = 90.......... (II)
Adding (I) and (II) we have
3x = 150
⇒⇒ x = 150
y = 10
Number of questions he got wrong is 10.