Answer:
4 pm
Step-by-step explanation:
We are looking for the time it takes for both trains to travel the same distance.
distance = unknown, but it is the same for both trains
train 1: speed = s = 60 mph, time = t, distance = d
train 2: speed = s = 80 mph, time = t - 1, distance = d
speed = distance/time
distance = speed * time
Train 1:
d = 60t
Train 2:
d = 80(t - 1)
The distances, d, are the same, so
80(t - 1) = 60t
80t - 80 = 60t
20t = 80
t = 4
It takes 4 hours after the first train leaves for the second train to catch up to it, so the second train catches up to the first train at 4 pm.
Answer: 4 pm
