In a competitive examination, 5 marks are awarded for each correct answer, while 2 marks are deducted for each wrong answer. Jayant answered 120 questions and got 348 marks. How many questions did he answer correctly?

Let the number of correct answers = x

Let the number of wrong answers = y

Total no of questions attempted = x + y = 120

⇒ y = 120 - x ….[1]

Marks for each correct answer = 5

Marks for x correct answers = 5x

As 2 marks are deducted for each wrong question,

Marks deducted for y wrong answers = 2y

Total marks obtained by student will be 5x - 2y,

⇒ 5x - 2y = 348

⇒ 5x - 2(120 - x) = 348

⇒ 5x - 240 + 2x = 348

⇒ 7x = 588

⇒ x = 84

Hence, no of correct answers = x = 84