The Missing Dollar Problem

Three friends went to a hotel. The bill was Rs $75
Each one contributed $25. The waiter took the bill to the cashier.
The cashier was happy & decided to give them a discount of
$5 and asked the waiter to return them $5.

Now the waiter was confused. How to distribute $5 among 3
persons?

He kept $2 in his pocket and gave $1 to each one
of the 3 persons. So initially each one had contributed
$25. Now as they are Given $1 back, their contribution
reduces to $24. They all contributed $24. ie
24x3=72 and 2 dollors are in the waiters pocket.
The total becomes $74. But they had paid $75.
Where is the remaining $1?