Question

In a Math contest consisting of 30 problems, Lydia was awarded 12 points for each correct answer, and 7 points were subtracted from her score for each wrong answer. No points were awarded or subtracted for problems not answered. How many correct answers did Lydia have if her score was 209?

Answer 1

Let x be the number RIGHT of questions
Amount scored for the x RIGHT questions = 12x
The end result is: 12x -7 = 209
12x = 216 and x = 216/12, x = 18.

So she had 18 correct answers (and 7 wrong)