Answer:
It was approximately a 9% decrease. (If you need to round to the nearest tenth, 9.1. If you need to round to the nearest hundredth, 9.10).
Step-by-step explanation:
I am going to assume that the question means that Andrea could have earned 220 points on the assignment, but instead because the assignment was late, she was marked down 20 points. (Reduced to 20 points is kind of awkward wording).
Given that, 20 divided by 220 comes out to 0.0909 repeating.
0.09, as a percentage, is 9%. (Again, 0.0909, 9.09%, could be rounded up to 9.1%).
Hope this helps!
