Again, the riddle: Fred, Jim, and Laura all set off down a road. Jim and Laura can walk at a top speed of 2 mph, and Fred can walk at a top speed of 4 mph. There is also a single bicycle which Jim and Laura can ride at 12 miles per hour and Fred can ride at 16 miles per hour (one cyclist at a time). What is the minimum amount of time for all three to travel 10 miles down the road?

Answer: This is the rare math puzzle that's actually a bit MORE complicated than it seems. It takes the use of linear programming to get to a solution of 2.75 hours. See http://www.rec-puzzles.org/index.php/BicycleAnswer for more.