Help how do I find the surface area ?

Asmall foreign car gete 42 miles per gallon and user 35 gallons on a trip.gasoline costs $1.05 per gallon.what was the cost of gasoline per mile driver?

Suppose that the price p (in dollars) and the weekly sales x (in thousands of units) of a certain commodity satisfy the demand equation 4p cubedplusx squaredequals38 comma 400. determine the rate at which sales are changing at a time when xequals80, pequals20, and the price is falling at the rate of $.20 per week.

Alonso walked with his friend andy one day, and wanted to compare their speeds. alonso walked 3 miles in one hour, and andy walked 2 miles in 2 hours. complete the table to graph the relationship for each person.