Please need help fast

Can someone me with the property questions for 12 13 and 14 plz

Which is greater, 7 p 5 or 7 c 5? 7p5 7c5

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%)