Answer: The speed is 105 miles/ hr and the direction of the train would be East if the girl is the frame of reference.
Step-by-step explanation:
Since we have given that
Speed of train = 100 miles per hour
Speed of girl = 5 miles per hour
Since the girl is moving towards the back of train.
So,it means train and girl are moving in opposite direction.
So, Relative speed would be
[tex]100+5=105\ miles/hr[/tex]
Hence, the speed is 105 miles/ hr and the direction of the train would be East if the girl is the frame of reference.