Answer:
40 students without a library card.
200 students overall
Explanation:
First of all, the 160 students with a library card are 80% of the students.
So we're trying to find 20% or how many have one over all? I'll answer both then.
First, you might want to set up a table or double number line if that helps. You should have 80%=160 filled in if you're doing that.
To find 20%, you should do 160 divided by 4. This is because %80 divided by 4 is %20, and 160 also needs to be divided by 4.
160 divided by 4 is 40. So 40 students don't have a library card.
To find out how many students there are overall, just do 40 plus 160 equals 200.