5more than 9 times x
a. 5(x + 9)
b. 9(x + 9)
c. 5x + 9
d. 9x + 5

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%)