15. You take a trip to downtown Boston to walk the Freedom Trail with your family. After you walk
through the Bunker Hill Memorial, your family decided to take a taxi to a restaurant for dinner. After 1
mile, the meter on the taxi says $475. It will cost $6.50 to go 2 miles. The cost varies linearly with the
distance that you have traveled (In other words, there is a constant rate of change).