This scatter plot shows the relationship between the amount of time, in hours, spent working on an essay and the grade, as a percent, earned. Enter an equation in the form y=mx+b that represents the function described by the line of best fit.

Astudent must have an average on five test that is greater than it equal to 80% but less than 90% to receive a final grade of b. devon's greades on the first four test were 78% 62% 91% and 80% what range if grades on the fifth test would give him a b in the course? ( assuming the highest grade is 100%)