Question 834056
What you mean is the difference in speed between the two planes was 25 mph.  Easily handled.  You must mean "2 hours" for "2h".


Slow plane is speed r.


______________speed____________time____________distance
Slow__________r________________2_______________r*2
Fast_________r+25______________2_______________(r+25)*2
Total__________________________________________510




Or did you want to do like this, letting r be the speed of the fast plane: 


______________speed____________time____________distance
Fast__________r________________2_______________r*2
Slow_________r-25______________2_______________(r-25)*2
Total__________________________________________510


Choose which way you like best.  Do you see what to do next?  You will make an equation for the total distance, which comes from the use of "total" and the column for "distance".