where is the $1???

Try Figure this out:
> >
> > Three guys in a hotel call room service and order two large pizzas.
> >
> > The delivery boy brings them up with a bill for exactly $30.00. Each
>guy gives him a $10.00 bill, and he leaves. That's fact!
> >
> > When he hands the $30.00 to the cashier, he is told a mistake was
>made.The bill was only $25.00, not $30.00. The cashier gives the delivery
>boy five $1.00 bills and tells him to take it back to the 3 guys who
>ordered the pizza.That's fact!
> >
> > On the way back to their room, the delivery boy has a thought... these
> >guys did not give him a tip. He figures that since there is no way to
>split $5.00 evenly three ways anyhow, he will keep two dollars for himself
>and give them back three dollars.
> >
> > OK! So far so good! He knocks on the door and one fellow answers. He
> >explains about a mix up in the bill, and hands the guy the three
>dollars, then departs with his two-dollar tip in his pocket.
> >
> > Now the fun begins!
> >
> > Remember $30-$25=$5 Right? $5-$3=$2 Right?
> >
> > So what's the problem?
> > All is well, right?
> >Not quite. Answer this:
> >
> > Each of the three guys originally gave $10.00 each. They each got back
> >$1.00 in change. That means they paid $9.00 each, which times three is
> >$27.00. The delivery boy kept $2.00 for a tip.
> >
> > $27.00 plus $2.00 equals $29.00.
> > Where is the other dollar ! ??????????