Twenty people stand in a row facing north. Priya is 3rd from the left end, Qasim is 8th from the left end and Ruchi is 5th from the right end. First Priya and Qasim interchange places, and then Qasim and Ruchi interchange places. What is Priya's final position from the right end?

Explanation

1. 01

   Ruchi from the left $= 20 - 5 + 1 = 16$. Start: Priya 3, Qasim 8, Ruchi 16 (from the left).

2. 02

   First swap: Priya 8, Qasim 3.

3. 03

   Second swap (Qasim and Ruchi): Qasim 16, Ruchi 3. Priya does not move and stays 8th from the left.

4. 04

   Priya from the right $= 20 - 8 + 1 = 13$.