Ploy is hoping to get a 90% on her math test, but she would be happy with any score within 10 points of 9. Find the range of score ploy would be happy with on her math test.
"Within ten points of nine" is a bit hard to understand. The most obvious way is that it's a 100-point exam, and 90% +/- 10 percentiles, or 90 points +/- 10 points, means that 80 pts plus is enough?
