Question

in a competitive examination there was 60 questions the correct answer would carry two marks and for incorrect answer one mark would be subtracted Yashwant attempted all the questions and he got total 90 marks then how many questions he got wrong
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Answer 1

Answer:

Let the no of questions he got wrong be 'x'

And the no of questions he got right be 'y'

As, he attempted all the questions,

⇒ x + y = 60

⇒ y = 60 - x eq.[1]

Also, he carries 2 for each corrects question and (-1) for each wrong question, also he got 90 marks

⇒ y(2) + x(-1) = 90

⇒ 2y - x = 90

⇒ 2(60 - x) - x = 90 eq.[Using 1]

⇒ 120 - 2x - x = 90

⇒ -3x = -30

⇒ x = 10

⇒ he got 10 wrong questions.