John had $50 (Dollars).He brought the Study material in $50.first upon he brought the School bag in $20.Out of $50 remained balance is $30 after that he brought book's to $15.The balance remained in his hand was $15 then he brought Compass to $9 out of remained $15 then he brought Pen to $6 out of $6 then balance was zero.Now he had no anymore balance remained in his hand.
He wanted to recalculate whatever he brought. The Expenditure on study material to balance remained as ... per listed like...
Expenditure | Balance $20 $30 $15 $15 $9 $6 $6 $0 +___________ +___________ $50 - $51
here john calculate but the answer was too different in recalculation john could not understood.He calculate he found the sum of total expenditure was $50 where the sum of total balance was $51 .From where does this extra one came from in balance.
What do you think ?