How much did the owner actually lose in total?

Question

A lady walks into a store and steals $100 from the register without the owners knowledge. She comes back 5 minutes later and buys $70 worth of goods with the $100 bill. The owner gives her $30 in change, how much did the owner lose?

Answer 1

It is time to think like an accountant or a banker in terms of credit and debit.

Here is an example of a normal transaction (selling 1 coat for $50; that is, for $50, the store has 1 less coat):

              CREDIT                         DEBIT
               $50                              1 coat

Here are the steps in the problem:

               CREDIT                      DEBIT                     NOTE
[1]             $0                           $100                   theft

[2]          $100                                                   original $100 bill
                                                 $30                     change
                                              Goods                  $70 worth
------------------------------------------------------------
              $100                $100 + $30 + goods

NET:    $100 – ($100 + $30 + goods)                    [NET = Credit - Debit]

The net effect is that the shopkeeper loses (debit) the $100, but in the sale, he gains $100 and loses(debit) $30 in change and loses $70 worth of goods. He is out $100 (the theft); the sale itself is legitimate.

Answer 2

The owner would still lose the $100. Because the $70 the owner regained as a result of this purchase was in exchange for goods the owner gave away. Alternatively, you can think of this as:

The owner lost $30 and he lost goods worth $70. 

Answer 3

The owner lost $100, $70 in merchandise and $30 in change.