Solve this simple math problem (you may not get it right :D)

[PhilS]

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[PhilS]

Quote:

Originally Posted by sonicm Throw away the bad money? Why is it 'bad'? Your paying the neighbor back makes it legal.

Yeah, you're right. Need to rethink this.

 

[hYdrociTy]

Chesebert, your name + that running truck + this ambiguous question all meld into one big chunk of hydrocitywantstohugyoureallybad

 

[PhilS]

It seems to me, upon further thought, that a significant problem and source of possible different answers is that the initial question is ambiguous in asking how much you are "in the red." It's not clear what that means, i.e., actual monetary loss, loss of value of assets, etc. But in the end, it seems to me you are out $10 plus the fair market value of the phones (whatever that is.) The $10 comes from the fact that you have to give the $90 in "good" money back to the store owner to replace the $100 fake bill you gave him, plus you have to come up with an additional $10 in good money to make up for the change you gave to the buyer. And you no longer have the phones.

P.S. I reserve my right to change my answer again.

 

[Azure]

You buy the headphone for $80.
-$80 Total

You sell it for $90 but get $100 first.
+$20 Total

Give $10 to the customer after you get change.
+$10 Total

Have to give $100 out of your own pocket to the neighbor because the buyer gave you a fake.
-$90

Net: -$90

I don't get what's so confusing/challenging, unless I did it wrong?

 

[nikongod]

you are not in the red at all.

you are infact a few beans ahead.

you call the fed's and tell them you have been passed a fake $100. when they arive they give you a real $100 note, and take the fake along with the information of the bad-note-passer.

 

[kunuggs]

negative 170 dollars

 

[PhilS]

Adding to my previous post, there is a real problem in determining the actual total value of the loss, because there is no legitimate basis (from the facts given) to determine the current fair market value (FMV) of the lost phones. The fact that they cost $80 (without any other facts) does not establish the current FMV. Nor does the fact that the buyer was willing to pay $90 establish FMV (assuming he knew the bill was fake), because he was not willing to part with $90 of real currency for them. Thus, again, it seems to me that the farthest one can go is to say you're out $10 cash plus whatever the FMV of the phones is at the time of the transaction, whatever that might be.

 

[axion]

Quote:

Originally Posted by stewtheking Did you think this up yourself?

I heard a similar question in my physics class a month or so ago. It came from a book of lateral thinking questions IIRC.

 

[chesebert]

This is what I replied in my PM to Zenith
"The answer is $100

$90 from the loss (substantive loss)
$10 from loss by lost profit (lost volume doctrine, since the headphone shop has an infinite supply of headphones if he sold the headphone to anyone else he would have made $10). You may also call this opportunity cost, but its really lost profit or lost volume to be precise.
"

 

[flamerz]

I agree with nikongod.

 

[JahJahBinks]

the question has been around in other forms for a long time, the trick part is the fake bill, answer is kinda counterintuitive.

 

[PhilS]

Quote:

Originally Posted by chesebert This is what I replied in my PM to Zenith "The answer is $100 $90 from the loss (substantive loss) $10 from loss by lost profit (lost volume doctrine, since the headphone shop has an infinite supply of headphones if he sold the headphone to anyone else he would have made $10). You may also call this opportunity cost, but its really lost profit or lost volume to be precise. "

You're still making assumptions that are not really set forth with any clarity in the initial hypothetical. For example, stating in the initial thread that "You bought a headphone for $80 and plans [sic] to sell it for $90" and that the seller is a dealer doesn't necessarily provide enough information to conclude that there is a $90 FMV, and in turn a $90 "substantive loss." It may be that this is what you intended to convey, but it would be more clear if the hypothetical stated that the FMV of the phones was $90, or whatever it is supposed to be. Also, the "infinite supply of headphones" is not in the original hypothetical either.

In event, this was a good brain teaser.

 

[chesebert]

Quote:

Originally Posted by PhilS You're still making assumptions that are not really set forth with any clarity in the initial hypothetical. For example, stating in the initial thread that "You bought a headphone for $80 and plans [sic] to sell it for $90" and that the seller is a dealer doesn't necessarily provide enough information to conclude that there is a $90 FMV, and in turn a $90 "substantive loss." It may be that this is what you intended to convey, but it would be more clear if the hypothetical stated that the FMV of the phones was $90, or whatever it is supposed to be. Also, the "infinite supply of headphones" is not in the original hypothetical either. In event, this was a good brain teaser.

you have to know what lost volume doctrine is and how it applies to this case. That's all

 

[JahJahBinks]

That reminds me this problem:

Three people decide to stay at a hotel at a rate of $100 per night, so they paid $300 total. The next day hotel owner realized he made a mistake on the price and returned $50 to them. However guy working at the counter only returned $30 to them, and put the rest $20 in his own pocket. So now each of the three people got $10 back, which means each only paid $90, total $270. But when you add that money to the $20 they suppose to get too, that's only $290, where is the missing $10?

Problems like this one and the one stated in this thread have made great interview questions