Please help me with this one! :)
(100 points!!!)

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%)

28 x 12 + 34 = ? it's for a test that if i fail on i will not proceed into the honor roll society i always dreamed of!me! worth 50 !

Five friends found a dollar on the ground and decided they each should get 1/5 of it. what amount of money will each friend get? $0.05 $0.20 $0.30 $0.80