PCS > Chapter 2 > Lesson 2.3.3 > Problem 2-157 Suppose a car drives 30 miles an hour for 2 hours, 40 miles an hour for one hour, and 50 miles an hour for half an hour. a How far does the car travel?

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%)