In a row 'A' is in the 11th position from the left and 'B' is in the 10th position from the right. If 'A' and 'B' interchange, then 'A' becomes 18th from the left. How many persons are there in the row other than 'A' and 'B'?

Let's calculate the total number of people in the row first:
1. Initially, B is in the 10th position from the right.
2. After A and B interchange positions, A occupies B's former spot.
3. This exact spot is now stated to be the 18th position from the left.

Using the total capacity formula:

$$\text{Total Persons}=(\text{Position from Left})+(\text{Position from Right})-1$$

$$\text{Total Persons}=18+10-1=27$$

The question asks for the number of individuals in the row other than A and B themselves:

$$\text{Remaining Persons}=27-2=25$$