A survey found that 6 out of 8 students own a pet. If there are 480 students in a school, what is a reasonable prediction for the number of students who do NOT own a pet?

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%)