Four people need to cross a bridge at night. They have one flashlight for the four of them, but the bridge is only wide enough for two to cross at a time. Because it's so dark, anyone crissing the bridge must do so with the flashlight.

Person A can walk across in 1 minute. Person B takes 2 minutes; person C -- 5 minutes, and finally person D needs a full 10 minutes to cross. Naturally, if two people are crossing the bridge, they move with the speed of the slower person.

What is the shortest amount of time it will take for all four to get to the other side?

Person A barks out the order 'Forward march!'  Person B carries the flashlight high at his inner side lighting a wide beam for all of them.  (Not necessary with proper military formation). Person D calls out cadence since he is the slow one.  Person C being a good little recruit follows along in step with the rest.  They walk two by two in ten minutes.

A is obviously the Marine, B is in the Army, C is the sailor, leaving D as the Air Force pansy.  It is a good thing we did not have a coast guard wimp.

Posted by john on 2005-06-16 19:47:56