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?

(In reply to solution by Charlie)

Tacking may allow the boat to move faster than 12 knots but it doesn't seem possible for component of the boats movement that is in the direction of the wind to be faster than 12 knots.  Thus, I think that the fastest speeds may be possible during the first heat but the fastest times (due to there being some sort of resistance in heat 1) should be in heat 2 (though the answer does not really seem that satisfying)

Posted by Joel on 2007-02-14 00:02:12