How many test question answered correctly.

Question

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 1

x = # answered right

 

23- x = # wrong

 

5x - 2(23 - x) = 73

 

5x - 46 + 2x = 73

 

7x = 119

 

x = 17

 

17 answered correctly