SOLUTION: In an examination, a student scores 5 marks for every correct answer and loses 2 marks for every incorrect answer. A student attempts 75 questions and scores 165 marks. How many qu

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equation Customizable Word Problems -> SOLUTION: In an examination, a student scores 5 marks for every correct answer and loses 2 marks for every incorrect answer. A student attempts 75 questions and scores 165 marks. How many qu      Log On


   

Question 1041651: In an examination, a student scores 5 marks for every correct answer and loses 2 marks for every incorrect answer. A student attempts 75 questions and scores 165 marks. How many questions did he answer correctly?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +n+ = the number of correct answers
+75+-+n+ = the number of incorrect answers
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+5n+-+2%2A%28+75+-+n+%29+=+165+
+5n+-+150+%2B+2n+=+165+
+7n+=+315+
+n+=+45+
and
+75+-+n+=+30+
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He answered 45 questions correctly
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check:
+5n+-+2%2A%28+75+-+n+%29+=+165+
+5%2A45+-+2%2A30+=+165+
+225+-+60+=+165+
+165+=+165+
OK