The roadblockClassical Mechanics Level 3
A bus, one hour after starting, meets with a roadblock that detains it for 30 minutes, after which he proceeds at 3/4 of its former speed and arrives 3.5 hours late. Had the roadblock been 144 kilometers farther along the road, it would have arrived only 3 hours late.
What is the length of the trip?
Clarification: The roadblock always detains a bus for 30 minutes and the bus then proceeds at 3/4 of the original speed.