Can anyone answers this trick question

There are 75 questions on a college examination. Two points are awarded for each correct answer, and 1/2 point is deducted for each incorrect answer. A score of 100 indicates how many correct and how many incorrect answers, assuming that all questions are answered?

55 correct.
20 incorrect.
75 questions answered.

55 x 2 = 110
20 x .5 = 10
110 - 10 = 100