Riddle
Three men are having breakfast in a cafe. The waiter gives them a bill for $25 and each man gives him a ten dollar note which he takes away and comes back with five one dollar coins. He gives each man a dollar and keeps the other two dollars as a tip. Now here is the problem: Each man gave $10 and received $1 back, so the paid $9 each. Three x $9 is $27 and the waiter has a $2 tip. That makes $29, so where has the other dollar gone?