You can
put this solution on YOUR website! Use RT=D concept and if you want to make some of the numbers and relationships clear, use a data table.
speed time distance
GOING 350 ( ) d
BACK 250 ( ) d
Total 3
Fill in the missing time information. This should enough to figure how to solve for both times each way and the distance either direction.
speed time distance
GOING 350 d/350 d
BACK 250 d/250 d
Total 3
;
Solve for d; you can get each of the time values if you want, using found d.