In a row of people facing north, Rekha is 7th from the left end and Salma is 12th from the right end. Exactly 4 people stand between Rekha and Salma. How many people are in the row?

Explanation

1. 01

   Salma to the right of Rekha: Salma is $7 + 4 + 1 = 12$th from the left, so the row has $12 + 12 - 1 = 23$ people.

2. 02

   Salma to the left of Rekha: Salma is $7 - 4 - 1 = 2$nd from the left, so the row has $2 + 12 - 1 = 13$ people.

3. 03

   Both cases fit every clue, so the row has 13 or 23 people.