Answer:
Peter missed five questions.
Explanation:
Since the test has twenty-five questions, and Peter got 80% correct...
80/100 = __/25 <--What number is the numerator?
Well, to get from 100 to 25, you have to divide by 4. 100/4 = 25.
Now, what is 80/4? If you do the math, you should get 20.
25 (Total Questions) - 20 (Questions Correctly Answered) = 5 (Questions Incorrectly Answered)