The total cost of an item including sales tax is directly proportional to its price. if the total cost of a $25 item is $25.75, what is the total cost on a $60 item?

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%)