Question: When you normally drive the freeway between Sacramento and San Francisco at an average speed of 115km/hr (71.5 mph), the trip takes 1.00hr and 13.0 min. On a Friday afternoon, however, heavy traffic slows you down to an average of 100km/hr (62.1 mph) for the same distance.
Part A: How much longer does the trip take on Friday than on the other days?
If possible just a brief explanation how you got the answer?