A LOST RUPEE

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
N ow 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?.