A sailboat race is held on a river that runs directly North to South, with a current of 12 knots. A 25 mile race is held going downriver (south). The first heat is held early in the day when there is no wind. The second heat, also going downriver, is held later, when there is a 12 knot tailwind (from the North). In which heat are the fastest times recorded?

There must be some kind of trick. In the first case, you don't need/use the sails, ,and just float along the river at 12 knots. And in the second case, if the tailwind by chance happened to make you go slower (??) you could just lower the sail, and just go downstream as in the first case.

Posted by e.g. on 2007-02-12 14:23:26