50

shreya.
Two tourists who are at a distance of 40 km from their camp must reach it together in the shortest possible time . they have one bicycle which they decide to use in turn. One of them started walking at a speed of 5km/hr and the other rode off on the bicycle at a speed of v2=15 km/hr . the tourists agreed to leave the bicycle at intermediate points between which one walks and the other rides . what will the mean speed of the tourists be ? how long will the bicycle remain unused.?

Question

50 

shreya. 
Two tourists who are at a distance of 40 km from their camp must reach it together  in the shortest possible time . they have one bicycle which they decide to use in turn. One of them started walking at a speed of 5km/hr and the other rode off on the bicycle at a speed of  v2=15 km/hr . the tourists agreed to leave the bicycle at intermediate points between which one walks and the other rides . what will the mean speed of the tourists be ? how long will the bicycle remain unused.?