A person steals Rs. 100 from a store without the owner noticing. Later he returns to the same store and uses that stolen Rs. 100 note to buy goods worth Rs. 60, receiving Rs. 40 back as change. Considering both the theft and the purchase together, how much total money does the store owner lose in rupees?

Introduction / Context:
This is a popular logical profit and loss puzzle. Instead of simple percentage calculations, it tests whether you understand how cash and goods move between the thief and the store owner. The key is to track what the owner finally loses in both money and goods after the entire sequence of events, not just the initial theft.

Given Data / Assumptions:

• A person steals Rs. 100 from a store.
• Later he buys goods worth Rs. 60 using the same stolen Rs. 100 note.
• The store owner gives him Rs. 40 as change.
• We assume there are no other transactions or recoveries.
• We must find the net loss to the store owner.

Concept / Approach:
We analyse the transaction in two parts. First is the theft, where the thief takes money without giving anything in return. Second is the later purchase, where the thief uses stolen money to buy goods and receive change. We must consider the store owner point of view: how much cash and how much stock leave the store, and how much real value comes back. It helps to classify the flows as loss of cash and loss of goods, then add them.

Step-by-Step Solution:
When the person steals Rs. 100, the store loses Rs. 100 in cash immediately.Later, the thief returns and uses this same Rs. 100 note to buy goods worth Rs. 60.From the store perspective, the Rs. 100 that it receives is actually its own money returning, not new income.In the purchase, the store gives away goods worth Rs. 60 and also gives Rs. 40 as change.Therefore, during the purchase, the store loses goods worth Rs. 60 plus Rs. 40 in additional cash, totalling Rs. 100.Combined with the original loss, the net loss in goods and cash is Rs. 100 from the theft plus Rs. 60 in goods plus Rs. 40 in cash.However, the Rs. 100 note returned during the purchase cancels the initial cash loss, so we track final position: only goods worth 60 and cash of 40 are gone.Hence the final effective loss is 60 plus 40 equals 160 rupees.

Verification / Alternative check:
Think of the thief as walking away finally with two things: goods worth Rs. 60 and cash worth Rs. 40. That total benefit to the thief is Rs. 100 in value. All of this value must have come from the store, because the thief had no genuine money of his own in the whole process. Therefore, the store must have lost Rs. 160 in total. This alternative viewpoint confirms the earlier calculation, because the store wealth decreases by exactly the amount of cash and goods that the thief ultimately possesses.

Why Other Options Are Wrong:
Option 200 rupees counts the original stolen 100 rupees and the later 60 plus 40 again without cancelling the return of the stolen note. Option 100 rupees considers only the value of the goods or only the initial theft but not the change in both steps. Option 40 rupees is clearly too low because the store lost more than just the change; it also lost goods. Only the value of 160 rupees correctly represents the store final loss in cash and goods together.

Common Pitfalls:
Many learners double count the stolen 100 rupees or forget that when the thief pays with the stolen note, the store is simply getting its own money back. Others focus only on the goods worth Rs. 60 and ignore the extra cash of Rs. 40 given as change. The safest method is to analyse the final situation: how much value is in the thief hands and how much has left the store. That complete view avoids the confusion caused by intermediate exchanges of the same note.

Final Answer:
The store owner total loss, combining goods and cash, is Rs. 160.