Bob, Bill, and Bo went on a geocaching trip. Their budget required them to share one car and one motel room. They found a cheap motel room in Vienna for only $30. Each man pulled out $10 and paid their share. Bob slept on the bed. Bill slept in a chair. Bo grabbed a pillow and slept in the bathtub. The next morning, they went down for the free continental breakfast and it was all gone. They complained, so the manager told the desk clerk to give them a $5 discount.
From the original $30, $25 was left in the till. The clerk couldn't figure out how to split the $5 refund three ways, so he gave each of the three men back a $1 bill and then slipped the remaining $2 into his own pocket. The travelers were thrilled. Instead of $10 each, the $1 they got back meant that the room had only cost $9 per person.
So... each of the three men had given the clerk $10 and received $1 each back. The clerk pocketed $2.There is still $25 in the till. That only accounts for $29. The men had paid $30. Where the heck did the other $1 go?
{I put it in the cache for whomever wants it.}.
You can check your answers for this puzzle on Geochecker.com.
5/20/10: lowered difficulty to a 2.5.
8/25/14: edited hint due to www changes.