Answer:D. The third train is faster than Train 2 but slower than Train 1.
Step-by-step explanation:
Since, If the speed of one object is greater than that of other object then we can say that one object is faster than other object.
Here, the speed of third train = 15/3=5 feet/sec ( because speed = distance/time)
And, according to the given graph the speed of train 1= 30/5=6 feet/sec ( by taking the approximate value of x and y by the graph)
While, the speed of train 2= 20/5= 4 feet/sec
Thus, we can say that, Speed of train 1>Speed of train 3> Speed of train 2
Therefore, Only Option D is correct.