Once A, B & C went to a restaurant. After having tea and light refreshment they asked for bill, the amount of bill was $30. They decided to pay the bill amount on equal share. Everybody took out $10 from their pocket and paid the bill.

They were yet sitting and gossiping in restaurant, Suddenly the waiter realized that the amount of their bill was $25 not $30. He took $5 from counter and decided to return them. Then he thought they are 3 people, how will they share $5? So he has decided to keep $2 to him and return only $3 to them. He came to their table and returned them $3 with apology. Everybody took $1 and put in their pockets.

Now my question is first time everyone paid $10 later they get $1 refunded.

So everybody paid $9.

$9 X 3 = $27

The waiter put $2 in his pocket.

$27 + $2 = $29

So...... Where is the remaining $1 ???

errr...ok so where where?