Trick Question

Three friends shared a meal at a restaruant. Each paid $10 for the meal. The manager realised that he should have charged them only $25 and sent the waiter back to their table with the $5 to repay them. The men could not share the $5 evenly so they told the waiter to keep $2 and they each took $1 back. Hence each man paid only $9 (3 men= $27) and the waiter kept $2 which makes $29.
What happened to the other dollar?

This is a question that I was really stumped on until I read the answer. The answer makes perfect sense.