Ihave no idea what i am doing. here is one of my problems,

a gas station sells 1500 gallons of gasoline per hour if it charges $ 2.10 per gallon but only 1300 gallons per hour if it charges $ 2.95 per gallon. assuming a linear model

(a) how many gallons would be sold per hour of the price is $ 2.70 per gallon?
(b) what must the gasoline price be in order to sell 800 gallons per hour?
(c) compute the revenue taken at the four prices mentioned in this problem -- $ 2.10, $ 2.70, $ 2.95 and your answer to part (b). which price gives the most revenue?