A student rides a bicycle to class every day, a round trip of 10. miles that takes 30. min in each direction. The student burns 420 kJ · h^–1 cycling. The same round trip in an automobile would require 0.40 gallons of gasoline. Assume that the student goes to class 150 days per year and that the enthalpy of combustion of gasoline can be approximated by that of octane, which has a density of 0.702 g · cm^–3 (3.785 L = 1.000 gallon). What is the yearly energy requirement of this journey by

(a) Bicycle and

(b) Automobile?