Can someone help me with this?

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%)

Which problem would you use the following proportion to solve for? 24/x = 40/100 a. what is 40% of 24? b. what percent is 24 of 40? c. twenty-four is 40% of what number? d. forty percent of 24 is what number?

Abox of chocolates cost $7 which equation relates the number of boxes sold parentheses x parentheses and total cost of the boxes sold parentheses y parentheses