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Iq 130+ simple but confusing brain teaser.

  1. Oct 11, 2007 #1
    you are a jewelry shop owner.

    one day a customer comes in to buy a $70 ring. He only has a voucher worth $100. you do not have any cash around, so you go next door to the pastry shop and ask the owner to change the $100 voucher for cash. the pastry shop owner gives you the cash.

    you go back to your shop and give the customer $30 in change along with the ring.

    10 minutes later, the pastry shop owner comes in angry and tells you that the voucher is fake, and that he wants his $100 back. you apologize and give him the $100.

    question: What is your total loss? (the ring indeed is $70)

    many have answered this wrong. please think it through.
  2. jcsd
  3. Oct 11, 2007 #2


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    $130 ?
  4. Oct 11, 2007 #3
    I'd say 100 $.

    Here is my explanation :

    Suppose the ring is exactly 100 $. Going to plastry shop to exchange the voucher would be useless (has he wouldn't have to give any cash back), but let's do it : he exchanges the voucher for cash, and afterwards the plastry shop owner comes back and takes his money back. Then the jeweler would have lost the price of the ring, which is 70 $.

    However the ring isn't 100 $, it's 70 $. So the jeweler gives back 30 $ in cash.

    Finally, he has lost 70 + 30 = 100 $.
  5. Oct 11, 2007 #4


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    I should stick in an explanation -- you lose $70 on the ring, $30 to the customer and $30 to the baker...

    or am I missing something as I chomp on my lunch...? :biggrin:
  6. Oct 11, 2007 #5

    The jeweler lost $100, the customer gained $100, and the baker neither gained nor lost.

    Assuming the voucher to be a worthless piece of paper, I won't mention it any longer
    The customer received a $70 ring and $30 cash and gave nothing in return for it. He made $100.
    The baker gave the jeweler $100 and the jeweler gave the baker $100. Neither the jeweler nor the baker gained nor lost on this transaction.
    The jeweler gave the customer a $70 ring and $30 cash and got nothing in return for it. He lost $100.

  7. Oct 11, 2007 #6
    I don't get this (and haven't yet looked at jimmysnyder's anwer). If you had no cash at the start, received $100 cash from the baker, then gave $30 to the customer, how did you have $100 to return to the baker? It seems you'd have only $70 cash left.
    In any case, if we are to assume that somehow you gave the baker $100 back, let's say you wrote him a check, then it sure seems to me that you're out that $100, but that seems like the "obvious" answer to me, so I assume it's wrong.
    Am I missing something?
  8. Oct 14, 2007 #7
    You lose 100 $....imagine u lost the voucher(same as fake.) All u did is u borrowed 100$ from neighbour and repaid 100 $ to him again. All u lost was ur ring (70$) and additional 30 $. That makes a total loss of 100$
  9. Oct 15, 2007 #8
    :/ I thought since the Jeweller gave away $100 to the neighbour, plus $70 ring and $30 change to the guy, wouldn't it be $200 all-together? XD
  10. Oct 15, 2007 #9
    $100 indeed. The owner makes a loss of $70 from the ring. The $100 he received is now only $70 (because he gave $30 to the purchaser). He thus has to throw in $30 from his own pocket.

    Or a much more simpler way of looking at this is, The customer did not pay the shopkeeper anything (since the coupon was fake). But the Shopkeeper paid the customer (effectively) $70 ring +$30 = $100.
    Last edited: Oct 15, 2007
  11. Oct 15, 2007 #10
    No, the $100 he gives to the neighbor is just the same $100 that the neighbor gave him, so his net loss is $100.

    The OP said many people get this wrong - is this the mistake they usually make?
  12. Oct 15, 2007 #11
    Even though the problem says the jeweler doesn't have any cash around but then pays the baker back, i'll ignore that little error. If the jeweler starts with "x" dollars, gets +100 from the baker (for the voucher), and gives the ring and -30 to the buyer, he is left with 70 dollars and no ring. Then when the baker comes back, he pays 100 dollars so is 30 dolalrs in the hole along with the ring.
  13. Oct 15, 2007 #12
    my answer is $200 due to the wording of the question.— it doesn't matter if the neighbor gave him that money in the first place; the question is "what is his total loss." even if he's giving the $100 to the same person who gave it to him, it was given to him, not lent, therefore he lost it.

    had the question been "what was his net loss from the transaction," I would've said $100.
    Last edited: Oct 15, 2007
  14. Oct 16, 2007 #13
    He has accepted a bad voucher. So he lost the $100. Thats all.
  15. Oct 16, 2007 #14


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    Staff: Mentor

    Has no one considered the fact that as a business the ring would not have cost him $70, unless he's crazy, the $70 price would have included a profit. So his "real" loss is unknown, since he might have never been able to sell that ring for $70 to a legitimate customer. :tongue2:
    Last edited: Oct 16, 2007
  16. Oct 16, 2007 #15
    Read again:

  17. Oct 16, 2007 #16


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    Staff: Mentor

    If the ring only cost the jeweler $20, his "real" loss on the ring was only $20, not $70.
  18. Oct 16, 2007 #17
    Yes, but in this case what would be the meaning of saying twice(!) the ring is $70?
  19. Oct 16, 2007 #18


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    Staff: Mentor


    I'm just getting nitpicky with the wording. The correct question would be what would be the anticipated, or projected loss. The real, or actual loss is unknown since we weren't told how much the ring cost the jeweler. :wink:
  20. Oct 16, 2007 #19
    nope. I stand by my word. he traded the voucher for $100 (made $100; it does not matter that the voucher is not actually worth the $100; he did make a $100 transaction), then he had to give back the $100 (that's him losing $100 and gaining nothing). then the $100 from the rest of the deal (the 70 + 30) = $200 gross loss and $100 net loss.

    the wording of the question implies gross loss.

    evo is also right, unless he's a terrible businessman, he would not have payed $70 for something he'll be selling at $70... and what about taxes? percentage of his earnings going towards employees, insurance? ... I dunno, this question is hard to answer without being given all the necessary info. I demand tax return print-outs and receipts!
  21. Oct 17, 2007 #20


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    When I get into work I'm gonna get some friends together and act this out -- just to settle it once and for all... :wink:
  22. Oct 17, 2007 #21
    I agree with belliot

    if he didn't have $30 to make change for the 100, then he couldn't pay back the baker. He only has $70 cash.

    But assuming he borrowed another $30 or wrote a check, then his loss is certainly $100 and kittle knight has the simplest explanation.
  23. Oct 17, 2007 #22
    loss= $70 ring + $100 paid to his neighbor
    gain= $70 in change from his neighbor

    net= $100
  24. Oct 23, 2007 #23
    The jeweler only lost $30 here, because from the $100 he borrowed from the baker, he had $70 of this still left over from the transaction with the customer because he had to give $30 of it away as change. So he only had to dig up 30 extra dollars to repay the baker.

    So the jeweler lost the ring + $30.
    Last edited: Oct 23, 2007
  25. Oct 24, 2007 #24

    Jeweler makes no money from the sale of these types of rings (I guess its a hobby for him or something).

    Given the fact that he only breaks even on sales of this particular ring, he had to shell out $100 to the baker.

    Basically the customer made $100 (ring plus $30 change) and the baker got back his loss of $100 which caused him to break even. So where did the $100 come from? The poor jeweler.

    Hope that makes sense.
  26. Oct 25, 2007 #25
    you can't convince me! muahahaha :devil:
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