Deanna gets 3 problems incorrect on a math quiz. Her score is 85%. How many questions are on the quiz?

20 questions.

Step-by-step explanation:

Let x be the number of questions on the quiz.

85 % means 85 out of 100 (or 85 / 100)

85 / 100 = 3/x

--->100-85=15

--->15/3=5

--->100/5=20

Meaning each question was worth 5% and there were 20 questions.