Ramesh walked 35 km, partly at a speed of 5 km/hr and partly at 3 km/hr. If he…

Ramesh walked 35 km, partly at a speed of 5 km/hr and partly at 3 km/hr. If he had walked at 3 km/hr for the time he actually walked at 5 km/hr, and at 5 km/hr for the time he actually walked at 3 km/hr, he would have covered 37 km instead. What was the total time (in hours) that Ramesh spent walking?