"Times are hard in a small rural town, business is slowing and people are moving out. It so happens that there are two horse-dealerships in town. Unfortunately there's only enough people to support one of the dealerships. So the two owners meet and decide that one of them must leave town. Since neither of them want to leave they devise a competition to see who gets to stay. It is decided that they will race their horses across town. Now they don't want to damage their horses, so they change the race rule so that whoever?s horse crosses the finish post LAST wins the race and gets to stay in town. So the next day they set off. Both are ambling along, taking rests and getting nowhere nearer to finishing. After a few hours a wise old man tells them to dismount and gives them some advice. After which the two sprint back to the horses, get on and gallop towards the finish line. Assuming that the race rules were not changed - what advice did the old man give them ?"
Simply to swap horses (whereby getting across the finish line first would ensure that the riders horse crossed last).