Step 1
Given;

Required; To determine where 1 banana went if 29 bananas are accounted for.
Step 2
Here is the break down; the balance should be like this;

Hence, there is no extra 1 banana, The monkeys spent 27 bananas of which the bellboy took 2 bananas and 25 bananas went to the room, and 3 bananas where returned to them. A total of 30 bananas