Two trains heading toward each other are 400 miles apart. One train travels 15 miles per hour faster than the other train. If they arrive at the same station in 5 hours, how fast is each train traveling?

2 answers

time = distance over speed
since the time is the same for both trains, and their combined distance is 400,

d/s = (400-d)/(s+15) = 5
d = 5s, so

(400-5s)/(s+15) = 5
s = 32.5
d = 162.5

check: 162.5/32.5 = 5
237.5/47.5 = 5
100