The 12th Man Challenge

Here was today's challenge question.  I have a friend who is a college professor who shared this with me.  You all did a great job working on it.  If you want to continue trying at home or share it with family, here you go!  Enjoy!

The   12^th Man Challenge

The Dodgen football team captains and their coach have a game that starts in 17 minutes, and they must all cross a bridge to get there.  All four guys (the captains) begin on the same side of the bridge.  Coach Wilkes has heard from the Mrs. Lattizori that you are one of Dodgen’s sharpest students and calls on you, an ardent fan and self-avowed “12^th Man,” to help them get across the bridge.  It is nighttime and there is one flashlight.  The rules of the bridge are as follows:

·       A maximum of two people can cross at one time.

·       Any party that crosses the bridge, either 1 or 2 people, must have the flashlight with them.

·       The flashlight must be carried back and forth; it cannot be thrown or otherwise transferred.

·       Each guy walks at a different speed, and a pair is limited to the rate of the slower man’s pace. 

o   Michael takes one (1) minute to cross the bridge

o   Paul takes two (2) minutes

o   Alan takes five (5) minutes

o   Larry takes ten (10) minutes to cross

For example, if Larry and Michael walk across first, 10 minutes have elapsed by the time they get to the other side of the bridge. If Larry then returns with the flashlight, a total of 20 minutes have passed and you have failed the team. 

Figure out how to get the four guys across the bridge without taking more than 17 minutes!  There are two known answers.