On a Trip, a Motorist Purchased Gasoline as Follows: 66

Essay

On a trip, a motorist purchased gasoline as follows: 66 liters at 69.0 cents per litre; 69 litres at 70.5 cents per litres; 80 litres at 71.5 cents per litre; and 57 litres at 74.5 cents per litre.
a) What was the average number of litres per purchase?
b) What was the average cost per litre?
c) If the motorist averaged 9.75 km per litre, what was her average cost of gasoline per kilometre?