Question 1053255
average=total/n
80=400/5
90=450/5
The sum of 4 is 338
400<=338+x<450
subtract 338 from everything
62<=x<112
62<=x, for all practical purposes. If the person gets greater than or equal to 62, they get a B. They can't get an A, unless there is extra credit that allows a score of 112.