Four investment bankers need to cross a bridge at night to get to a meeting. They have only one flashlight and 17 minutes to get there. The bridge must be crossed with the flashlight and can only support two bankers at a time. The Analyst can cross in 1 minute, the Associate can cross in 2 minutes, the VP can cross in 5 minutes and the MD takes 10 minutes to cross. How can they all make it to the meeting in time?

First, the Analyst takes the flashlight and crosses the bridge with the Associate.  This takes 2 minutes.  The Analyst then returns across the bridge with the flashlight taking 1 more minute (3 minutes passed so far).  The Analyst gives the flashlight to the VP and the VP and MD cross together taking 10 minutes (13 minutes passed so far).  The VP gives the flashlight to the Associate, who recrosses the bridge taking 2 minutes (15 minutes passed so far).  The Analyst and Associate now cross the bridge together taking 2 more minutes.  Now, all are across the bridge at the meeting in exactly 17 minutes.   Note, that instead of investment bankers, you’ll often see the same question using members of musical bands (usually either the Beatles or U2).