When Should Qasr be Performed and when not?

Q: Salaah-123: While I live in Baruch, I work in Bombay. I reached Baruch on the fifteenth, and will be returning to Bombay after three days. I intend staying in Bombay for twelve days before returning to Baruch for the Eid vacation. Will I now perform Qasr in the twelve days in Bombay or not?

Answer: In this case, you will perform Qasr because you intend staying only twelve days. And Allaah knows best what is most correct.

Fatawa Rahimiyyah vol.2