part A: graph A because the slope is 55/1 and the yintercept is at 0
the unit rate is 55 miles/1 hour
part B 45x=231 for the train and
55x=231 for the car
divide the first by 45 to get 5.13 hours
divide the second by 55 to get 4.2 hours
the difference is .93 of an hour faster.