Mathematical Twist

Three friends went to a hotel.
The bill was Rs 75/-
Each one contributed Rs.25/-.
The waiter took the bill to the
cashier.

The cashier was happy & decided
to give them a discount of Rs.5/- & asked the waiter to return them
Rs.5/-.
Now the waiter was confused.
How to distribute Rs 5 among 3 persons?
He kept Rs 2 in his pocket &
gave one rupee to each one of the 3 persons.
So initially each one had contributed
Rs.25. Now as they are given 1 rupee back, their contribution reduces to
Rs 24.
They all contributed Rs 24 --
that is 24x3=72 & 2 rupees are in the waiters pocket.
The total becomes 74. But they
had paid Rs 75.
Where is the remaining 1 rupee?????????