Mathematical Challenge!

Please write solution for my question:

Arun invested 4500 rupees, Ram invested 90000 after 3 months, Raj invested 60000 after 6 months in the same business. They got 20000 rupees profit after 1 year. What would be Raj's share in it?

I shall appreciate a quick response

My mail id is rayudu.obu@gmail.com