# HOW SMART ARE YOU? The Stolen Bill Riddle (Viral Math Problem) – The Correct Answer Explained

This problem is making the rounds on Facebook and Twitter with thousands of people arguing about the correct answer. How smart are you? A guy walks into a store and steals a $100 bill from the register without the owner’s knowledge. He then buys $70 worth of goods using the $100 bill and the owner gives $30 in change. How much money did the owner lose? $30, $70, $100, $130, $170, or $200?

My blog post for this video

http://wp.me/p6aMk-53H

Sources

Thanks to Eric for sending me this problem by email.

One version of the problem on Facebook with 20,000 shares:

https://m.facebook.com/story.php?story_fbid=1254756407914475&id=100001403825442

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If you assume that the guy didn't have any money and walk out with 70 dollar worth of goods and 30 dollar cash, then 123 problem solved, it is 100 dollar that the owner lost.

100 dollars, the owner loses 70 dollar from 70 dollar worth of goods +30 dollar from the change. The guy walks out with 100 dollars or equivalent (70 dollars worth of items +30 dollar change), without having to spend any of his own money, if he had any Money in the first place.

Very hard to be sure of which answer the Riddler wants… "$70 worth of goods"? was it worth $70 to both parties? … because if it was sold for $70 and the store owner paid $70 for the goods the store has bigger issues that overshadows this problem (no mark up, how does store owner stay alive even without theft??). Then there is the issue of the goods… do we see the goods as "money" or just as "goods"? In the story end the shop owner lost $30 in "money" but also $70(caveat: depending mark up) worth in GOODS. Total VALUE was $100(caveat: mark up?) but only $30 in cash money. So, $100 or $30… with reservations.

100 dollars

I think the explanation given is too complicated. See it this way: how much did the thief leave with? The goods worth $70 and $30 change.. that's it. He stole $100 hence this is the amount lost by the shop owner.

First answer I got right.

Call me dumb if you want, but in the problem it says how much money did he lose, not the value. Correct me if I am wrong. And he lost 30 dollars in money, he did lose 70 in the value of the goods which would make it a total loss of 100 in value, not money. That is my opinion, and if you have a different one I respect it.

(I am a 13 year old child in the 8th grade which would explain why I am not able to comprehend my flaw in logic if I am mistaken)

Life must be very hard for those that have difficulties with situations like this!

It could be 130 if he/she bought 70 in goods at another store, and the manager just gave him someone else's change, (the wording leaves room for various interpretation), also it could have been 30, he takes 100, gives back 70.

People will argue about anything.

100 dollars…

Whatever was left with that was not come in with. That simple…. unless you count profit margines in.

At the end of the day he's going to have 100 less than he otherwise would have.

So it's 100.

It's impossible to solve because we don't know the markup on the goods he sold to the man, he may only lose 10 dollars on 70 dollars worth of goods

Biggest problem with this question: it starts off by asking a question.

fb is full of dumbs fucks

But he got 70 back! Shouldn't it be 30

He lost 170

Not happy with this explanation at all. So here's another way: I steal $25 from you then turn around and use that to buy $20 worth of weed from you. You give me the weed and $5 change. I did not give you back your money, I used your money whereas I would have normally handed you my own money for the transaction making your pockets $20 fatter. But since I used your money to buy the weed, you out $25 I stole + $25 in weed and change. You lost $50 all together. Same as above. Just because he used the $100 he stole to gain more from my store, the owner should be out $200 all together because in an honest transaction my $100 would have stayed where it was, he would have given me another $100bill to pay for the merchandise and I would have given him $30 in change.

This was very easy compared to many other "riddles" on this channel. I don't think one has to be that smart to figure this out.

Lol $170 loss Yes the owner purchased the merchandise twice (investment X loss). The owner had to purchase it in order to sell it (purchase 1) and make a profit. The cash is an automatic loss. The merchandise is an additional loss as well (purchase 2). This is a great question because it's provoking us to really think. The thief can be omitted really and you can say that the owner lost $100 because either way… the owner will never see the profit of the $100 because he didn't gain anything after it was gone, not even the $30 n change. On top of that he in loss $70 in produce because again, the money was once earned by him, the items were bought by him initial… then he loss $100 and paid for the item again with the money that his to begin with plus the loss in profit. Lol that's not even mentioning the overhead expenses lol K I want to work at your store lol

Problem is, the till is off 100 and that will not change. adding a trAnsCtion does not invalidate the initial till.

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

A. $30B. $70C. $100D. $130E. $170F. $200DO NOT OVER THINK IT!

Again do not over think it…

First off it does not say how much money did the owner loose it says how much did the owner loose

100

He loses $100 that was stolen. However the problem doesn't specify that the goods were purchased WITH the stolen $100. Thus he is out $100 only. If we go with the logical assumption (and we know what happens when we ASSUME) that the stolen $100 was used to purchase the $70 (which if you are a store owner you are on the hook for) then it would be $170 of theft total. As the $30 in change would still be part of the original $100 that the thief stole. Remember context clue says DO NOT OVER THINK IT thus means it is a literal sentence structure so the $70 wasn't purchased with the stolen $100, so he's only out $100.

This is wrong cause what people are not considering is that first $100 that was accounted for was stolen. Now the register is $100 short.

So when somebody comes in and makes a purchase for $70 with $100 of your money you loose the change which is $30. Now the register is supposed to be at $570 but it's at $470. So the register is down $100, the thief walked out with $70 of merchandise and $30 of the owners money adding up to $200 lost

if the 100 dollars are his to begin with you can't say he made any gain during the transaction.

30$ is my answer.

First he loses 100$ obviously, but then he gets 70 of the dollars back. 30$ of change means nothing, it just means the stealer spent 30$ extra and got 30$ back.

Edit: I watched the explanation, and I disagree. The owner lost 30$ in actual cash, and 70$ worth of items. He lost 30 dollars but also lost 70 dollars in something that isn't cash. How much money did he lose? 30 bucks. How much value did he lose? 100$.dude your so wrong it's not funny

how the fuck you figure

So if he is running a 20% profit margin across the board the thief stole 80 dollars bought 56 dollars worth of goods and got 24 dollars in change the owner has a 80 dollars break even with a loss of 34 dollars in potential profit. You have factor in two sales transactions of 100 and 70 dollars to maintain margins. Going further if you are contending with variables like shelf life waste or multiple loans where you do not have stable principle reduction on a couple then you have to weight the transactions corresponding to cost at a given time. If I was running a business I would fix an acceptable profit margin and redistribute any profit after that so cost would hopefully be deflating constantly.

Basically, it's not so much a math problem, as it is a question of semantics.

Do you want the net change in financial position? Total cash in bills taken by the customer, ignoring bills returned? Do you value stolen goods at potential loss of earnings? Buy/Sell price?

The answer wholly depends on how you interpret the question.

The actual maths involved is trivial.

what the main thing that pisses me off is the fact people always says he gave back the $100 bill, NO HE DIDNT, he used it to buy something. once he left the store with no intention of returning it (without using it to buy their shit) then no, he didnt return the bill.

so we got a thief who stole $100 from the business. the business lost $100

the thief bought $70 worth of stuff with $100. Now since the money used to pay was the businesses money that to is a loss in profit.

and THEN the cashier gave $30 change FOR THE $100 THAT WAS THEIRS TO BEGIN WITH- thats another $30 loss

people got to remember we are talking about a business, it cant be solved in a literal sense. if you think that buying $70 worth of shit from a store using money you stole from them counted as "returning the bill" then go ahead and try that in real life.

I agree with your answer but have a suggestion for an interpretation of the 130$ answer.

Since the question isn't stated as "How much did the owner lose in total?" it isn't that clear that it's the net loss that's the answer.

I would like to discuss the meaning of the word lose.

If you lose three friends and gain three friends you can't come to the conclusion that you've lost 0 friends. If you lose 100$, then gain 100$ and then lose 30$ I think it's correct to say you lost 130$, you gained 100$ and your net loss were 30$.

I think it's discussable whether or not to take the goods into account.

If I lost a car and gained an airplane how many cars did I lose. Cars and airplanes are different things so the obvious answer is 1.

Money and goods also are two different things.

I know this is unconventional and probably is more of a language problem then a math problem.

when you have no life….

My answer was 30 cause I thought when you said money you meant cash

Can't figure it out without knowing the profits he makes off of the $70 worth of goods. It's probably in between 100and 130, though.

loss of $170

Yes technically it is 100$ because of the value of the goods, but if it was the loss of MONEY, then it would be

0+(-100)+100+(-30)= $-30, so a lost $30, but the VALUE he lost is $100

This video kills brain cells.

Someone probably wrote this already, but hey..

A fauly way of thinking is to even include the second part of the problem. The theif buying stuff is no different from an everyday customer buying something, hence the only real "loss" is the 100$ stolen in the first place.

The second part is called business no matter what. The owner made money after the initiall loss, not by any means cutting it shorter. It doesn't matter that the $100bill was the owners to begin with.

If our consideration is bound by only these transactions and not previous transactions regarding the acquisition of the store's inventory, and money is not to be confused with value, then the owner lost $30 of money.

i would say $160 < X < $170 because the owner bought the goods from the producer/manufacturer before selling

The value V is in fact and in any possible way 70 dollars. Even if he buys the goods for 30 dollar, its the fact of not being able to sell them for a certain amount that determines his costs.

Guy takes 100. -100. Guy gives 100. +100. Guy takes products. -70. He pays. +70. Owner gives change. -30. In total he lost $30.

the correct answer is 30 when you consider the question asks about money. The goods are not money. At the end of the story the owner handed the criminal 30 dollars.

I got $60 at first

i got 30 i still don't get it halp

i will claim it to be 70$. Let's say you own a store where you sale icecream. you get the icecream for 5$ will you sale it for 5$ or will you try to earn and will sale it for 7$.

If we consider the fact the owner shouls earn from his sales then he lose less than 100$ and if we consider the goods got some value it means he lose more than 30$(the change value) so we got 70$ between so.