Betty and Anna work at the same office in Philadelphia. They both must attend a meeting in Pittsburgh, so they decide to drive to the meeting together. Betty is a cigarette smoker and her marginal benefit from smoking a package of cigarettes a day is $40. Cigarettes are $6 a pack. Anna dislikes cigarette smoke, and her marginal benefit from a smoke-free environment is $50 a day. What is the outcome if
a. Betty drives her car with Anna as a passenger?
b. Anna drives her car with Betty as a passenger?