The distance is 24 miles.
The basic rule to remember in all problems involving distance, rate and time is:
Beyond that, you need to clearly identify any variables in the equations you write.
We seek the distance in this case, however it is often easier to use a variable for one of the rates (either for the train or driving) or one of the times. This avoids have to change
But the distance between home and work is the same in both cases!
Be careful, though, because the question did not ask for a rate! It asked for the distance.
We have the rate in miles/hour, but we have the time in minutes.
48 minutes =