Question

It is almost the end of the grading period.I have 730 out of 880 points so far in my math class which means I currently have a B (83%).There are 90 points remaining before grades come out.My teacher rounds each student's score to the nearest percent.What is the fewest number of points I need to get and end up with a grade of
C (At least 70%)
B (At least 80%)
A ( At least 90%)