Can anybody tel the answer??

ali (Student CA CPT ) (130 Points)

14 August 2014  

A lady buys goods of rs.200 (cost price of the shopkeeper) & pays a 1000rs note to the shopkeeper.he gets the change from the next shop & keeps 200 for himself & returns 800 to the lady.after sometime the next shop owner returns the 1000rs note saying it is 'duplicate' & takes the money back.how much loss did the shopkeeper suffer?