SOLUTION: On the 30 question physics exam, correct answers are worth 5 points, incorrect answers are worth -2 points and unanswered questions are worth 0 points. Pat answers 23 of the questi

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Question 1136912: On the 30 question physics exam, correct answers are worth 5 points, incorrect answers are worth -2 points and unanswered questions are worth 0 points. Pat answers 23 of the questions and scores 73. How many questions did Pat answer correctly?
Answer by greenestamps(13209) About Me  (Show Source):
You can put this solution on YOUR website!


23 answers all correct would give a score of 23*5 = 115.

Each question missed lowers the score by 7 points -- because you lose the 5 points for a right answer and lose 2 more points for the wrong answer.

So if 23 questions were answered and x of the answers were wrong, the score would be 115-7x. So

115-7x+=+73
42+=+7x
x+=+6

6 of Pat's 23 answers were wrong, so 17 of them were right.