A problem by Rahul Sharma
I have a pen whose cost is 200. a lady came to me to buy that pen from me and she gave me a 1000 rupees note but i did not have change so i took it from my near by store. I sold that pen to lady in 0% profit and returned her 800 rupees as her change. later on that shopkeeper came and told that this note is duplicate and i have to give him another one. what is the total loss for me.