Your £500 fell out from your pocket and someone picked it, the person who picked it happens to owe you £100.
So, the person paid you the £100 he owed you with the £500 and you gave Him Back A Change Of £400.
HOW MUCH DID YOU LOOSE IN TOTAL?
The Loser, The Gainer
#1 may be! I lost Rs.500
emo165#
#2 According to question as I understand 500 (lost) + 400 (mistaken return in change ) - 100( for change from person ) = 800 ( totall loss)