Question 252965
We are really told where the train is when he heard the train.
rt=d
t=d/r
We assume then that the time is the same for the train and the walker.
The train goes one unit and the walker goes 3/5

d/r=d/r
.60/r=1/60
multiply by 60
.60*60/r=1
multiply by r
.6*60=r
multiply by 10 to get rid of decimals
6*60=10r
360=10r
r=36 mph
Apparently the walker can run 36 miles an hour with a train after him.