Simple Math Question

Discussion in 'Physics & Math' started by deicider, Mar 1, 2011.

  1. Pete It's not rocket surgery Moderator

    Messages:
    10,166
    I don't see any way of parsing the OP to get:
    X = X + Y/2

    The book costs its cost plus half the price? What?
    It looks like you're trying to parse it two different ways and combine the result.
    First you ignore the "plus half its price" bit to say the cost is 1, then you remember the bit you forgot to add half the price anyway.

    Is that messing about? Or Taching away?

    Once Tach started on that tack, he consistently had cost=y, price=x

    The OP says that the book costs $1 plus half of its price.

    Cost = $1 + Price/2
    y = 1 + x/2

    Right?

    Note that adding another equation: x=y then gives the easy answer of $2.
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Messages:
    18,532
    The OP:
    What is the Cost of a book that costs 1$ plus half of its price?

    Method 1
    What is the Cost of a book that costs (1$) (plus half of its price)?

    Method 2
    What is the Cost of a book that (costs 1$) (plus half of its price)?
    See? Method 2 states that the book costs $1.

    Please Register or Log in to view the hidden image!



    No, I said that on the basis that it costs $1 the second portion is contradictory and should be ignored.

    The word "cost" is used twice. Using method two maintains that by using "x" twice.

    Agreed. Honestly.
    I'm just of the opinion that if we're going to keep the thread open on a question that was answered on page 1 (in post 2, no less) then let's be adult Sci about it. Bring on the frivolity!
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. Pete It's not rocket surgery Moderator

    Messages:
    10,166
    Only for the buyer. For the seller, cost means what they paid for it, not the price they're charging the buyer.
    So, it's a reasonable interpretation.

    I'm beginning to wonder if that was the OP's intent... the use of two different words seems deliberate. It might be that the author thought that using only "cost" or "price" would sound awkward, but if they deliberately changed it for that reason then they should surely have considered the ambiguity that arises?

    Try this:
    Cost = $1, Price = $0
    Cost = $1.50, Price = $1
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. Pete It's not rocket surgery Moderator

    Messages:
    10,166
    Firstly, you can only conclude that the cost is $1 if you ignore the "plus half its price" to begin with, so it's not contradictory. Ignoring those words is just wrong.
    Secondly, if those words are ignored then you're simply left with X=1. So where do you get X = X + Y/2?
    You can't have it both ways.

    Weasel! It doesn't parse that way. Try this:
    What is X, if X=1+Y/2

    Yes, frivolity is great... but dodging acknowledging mistakes? That's what Tach does.

    Please Register or Log in to view the hidden image!

     
    Last edited: Mar 3, 2011
  8. Pete It's not rocket surgery Moderator

    Messages:
    10,166
    But the buyer will surely pay the price that it costs.
     
  9. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Messages:
    18,532
    Because by putting it in the form X = X +Y/2 (i.e. directly as worded) shows that Y/2 should be ignored.
    I pointed out that X (by virtue of being X) must be X and that the Y/2 therefore doesn't come into it. It follows FROM expressing it in that form.

    I know!

    Yes!

    No, I laid it out in my post (way back...) as an illustration of how ridiculous the argument (that argument, mine) was.
     
  10. siphra Registered Senior Member

    Messages:
    344

    Is the question from the POV of a seller or a buyer.

    If your a buyer for anything cost == price
    if your a seller ideally cost < price
    unless its a loss leader.
     
  11. siphra Registered Senior Member

    Messages:
    344
    In which case, we're a sociology study as I earlier theorized.

    Please Register or Log in to view the hidden image!

     
  12. Pete It's not rocket surgery Moderator

    Messages:
    10,166
    No. Directly as worded, you get X = 1 + Y/2
    [the book] costs $1 plus half the price.
    Where did the $1 go in your equation? You have already changed it to X, justified by ignoring the "plus half the price" and setting X=1.

    Then why are you arguing otherwise?

    Well, I still think that your post 106 is clearly wrong, and it doesn't look like frivolity.

    *grumpy hat on*

    Please Register or Log in to view the hidden image!

     
  13. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Messages:
    18,532
    Cost = X.
    The book "costs $1" (from the OP).

    Bloody-mindedness and boredom.
    For my next trick I'll try to show that it really does = Christmas cake.

    Please Register or Log in to view the hidden image!

     
  14. Pete It's not rocket surgery Moderator

    Messages:
    10,166
    Isn't that what Tach said a couple of posts ago?
    Maybe it's a Dan Brown novel.

    Please Register or Log in to view the hidden image!


    $1 and $1.50 are *possible* but unlikely answers for the purchase cost / selling price interpretation.
    Anything over $2 is more reasonable.
     
  15. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Messages:
    18,532
    That's the answer!
    The book costs nothing because the Illuminati blew it up with anti matter while stealing the Mona Lisa.
     
  16. decons scrambled egg Registered Senior Member

    Messages:
    144
    "Cost" is not Star Trek, and "Price" is not Star Wars. This thread does not deserve this much attention even on a nerdy site.

    "Doesn't anybody notice this? I feel like I'm taking crazy pills!"(*)

    (*)http://www.imdb.com/title/tt0196229/quotes
     
  17. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Messages:
    18,532
    Since you're using movie quotes to support your point of view, here's one that supports ours:
    Animal House.
     
  18. decons scrambled egg Registered Senior Member

    Messages:
    144
    A very useful quote. It can cover a number of my point of views.
     
  19. Emil Valued Senior Member

    Messages:
    2,789

    Welcome among us! :worship:
    Hang on, buddy. :itold:
     
  20. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Messages:
    18,532
    An equally useful one from the same film:
    "You fucked up, you trusted us."

    Please Register or Log in to view the hidden image!


    That's come in handy a few times!
     
  21. Captain Kremmen All aboard, me Hearties! Valued Senior Member

    Messages:
    12,738
    So what was the answer then?
     
  22. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

    Messages:
    8,967
    This pretty much sums up most of SciForums.

    Fortunately, it doesn't really sum up this forum

    Please Register or Log in to view the hidden image!

     
  23. Captain Kremmen All aboard, me Hearties! Valued Senior Member

    Messages:
    12,738
    OK Smartarse.
    What's the answer?
     

Share This Page