Question

You answer 80% of the questions on a 20 question test. How many do you answer incorrectly?

Answer 1

4 answers would be incorrect.

Explanation:

100%-80%=20%

So using that, 20% of the questions are unanswered.

So you would use the 20 back from the expression and use:

20*20/100

And that equals 4, so the result should be 4 questions that were answered incorrectly.