Ok. Manab, the problem lies in the way the question is being asked. Here's the solution: Price paid by three guys should equal to the price recieved by the restaurant, right? And the price recieved by the restaurant = price recieved by the manager + price recieved by the bell boy, right? So, the guys paid $27 (3*$9) dollars in total for lunch (even though $25 was the actual cost), which is equal to what the manager recieved ($25) and what the bellboy recieved ($2). So, that $1 dollar which had you confused did not go anywhere; it got lost when the question was asked, and I have already said, the question has a flaw.