Trolley motion problem

[DivineNathicana]

"A double-track trolley line runs between two stations 6 miles apart. From each station cars set out for the other station every 7.5 minutes and proceed at uniform speed. A pedastrian leaves one station just as one car is arriving and another is leaving. He walks beside the right-of-way at constant speed until he reaches the other station just as one car is arriving and another is leaving. Including these 4, he saw 62 cars on his way, 19 going in the same direction and 43 in the opposite direction. What was his speed, and what was the speed of the cars?"

 

I figured that 18 cars caught up with the pedastrian (since the 19th left with him), and so that's 18x7.5=135 minutes to walk the 6 miles. That's 6 miles divided by 2.25 hours = 2+2/3 miles/hour = his rate.

 

From there, I'm a little lost. Help, please?

 

Thanks in advance,

 

- Alisa