• In an examination, a student scores 4 marks for every correct answer and losses 1 mark for every wrong answer. A student attempted all the 200 questions stud and scored 200 marks. Find the number of questions he answered correctly.
 A) 82 B) 80 C) 68 D) 60

 B) 80

Let the number of correct answers be x

and number of wrong answers be y

Then, 4x - y = 200 ...(i)

and x + y = 200 ...(ii)

On adding Eqs. (i) and (ii). we get

4x - y = 200

x + y = 200

5x = 400

Therefore, x = 80

##### Similar Questions
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III. intersecting, if the system has only one solution.
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