A train covered the distance of 400 km between A and B at a certain speed. On the way back it covered 2/5 of the distance at that same speed and then it decreased its speed by 20 km/hour. Find the speed of the train at the end of its journey from B back to A, if the entire trip took 11 hours.

Answer 1

Most of these distance-rate-time problems are basically the same.
I did the last one for you,
give this one fair try, and let me know at which point you get stuck.

Hint: let the "certain" speed be x km/h
then the slower speed is x-20 km/h

Answer 2

I am really stuck with creating the equation

Answer 3

First part of trip:
distance = 400 km
speed = x km/h
time = d/r = 400/x hrs

return trip
2/5 of 400 at x km/h, then 3/5 of 400 at x-20 km/h
how far did the train go at x km/h ?
how far did the train go at x-20 km/h ?
What is the time for the first part of this return trip?
What is the time for the 2nd part of this return trip

You now have 3 different times
What is the total of these times ???

form you equation.