Answer : 4 120 Explanation : Answer: D) 120 Explanation: let x be the correct answer and y be the wrong answerso the total number of questions is (x y) = 150.....(1)=

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In an objective competitive exam, a correct answer score 4 marks and on a wrong answer 2 marks are negatively added. A student scores 420 marks from 150 question. How many answers were correct ?