A group of enterprising engineering students has developed a process for extracting combustible methane gas from cow manure (don't worry the exhaust is odorless). With a specially adapted internal combustion engine, the students claim that an automobile can be propelled 15 miles per day from the "cow gas" produced by a single cow. Their experimental car can travel 60 mile per day for an estimated cost of $5(this is the allocated cost of the methane process equipment- the cow manure is essentially free)

(a) How many cows would it take to fuel 1,000,000 miles of annual driving by a fleet of cars? What is the annual cost?

(b) How does your answer to part (a) compare to a gasoline-fueled car averaging 30 miles per gallon when the cost of gasoline is $3.00 per gallon?