17 In a study of cell phone usage and brain hemispheric dominance an internet survey was emailed to 6990 subjects randomly selected from an online group involved with ears.

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%)