The problem states that a hotel has 40 rooms. 8 of the rooms are empty and the rest are rented. We are asked to find which equation can be used to find $r$, the number of rented rooms.

1. Problem Description

The problem states that a hotel has 40 rooms. 8 of the rooms are empty and the rest are rented. We are asked to find which equation can be used to find $r$, the number of rented rooms.

2. Solution Steps

We know the total number of rooms is

4

0. We know the number of empty rooms is

8. The number of rented rooms, $r$, is the total number of rooms minus the number of empty rooms.

So, $r = 40 - 8$.

The correct equation is $40 - 8 = r$.

3. Final Answer

$40 - 8 = r$