Suppandi and Bussiness Man

Suppandi’s master was a small time business man. He had told Suppandi to always try to earn a profit.
Master: Suppandi, I am expecting a washing machine from London Stores. Go and give this Rs.50 note to the shopkeeper and get the machine.
On the way back from the store, a man met Suppandi.
Man: How much did you buy that machine for?
Suppandi: Rs.50.
Man: I will give you Rs.90 for it.
Suppandi thought that he was making a profit and sold it and reached home.
Master: Where is the machine? Suppandi: I sold it off on the way for Rs.90, a clear profit of Rs.40.
Master: You fool, that machine was worth Rs.9000. I was paying for it in installments.
Master: Your Fired!!!