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Math Help - Old guys arguin over math from long ago

  1. #1
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    Old guys arguin over math from long ago

    So we have ave a math problem that we are arguing on. This started as an argument between two 40 year olds looking through kid's math books. Here is the problem:

    If there is 26 times more caffeine in a normal cup of coffee than in decaf and the total between them is 121.5 Grams of caffiene, how much is in each cup?

    While I have no clue how to solve it, I can verify answers (Thank god my old brain retains that ). My logic says that:
    Decaf + Regular = 121.5
    Decaf * 26 = Normal

    He is trying to tell me that Decaf = 4.67 and Caffien = 116.82. Rounded of course.

    I can tell this is wrong because while Decaf + Regular is true, Decaf * 26 is not.

    How can I prove him wrong here?



    Thanks!
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  2. #2
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    Re: Old guys arguin over math from long ago

    Quote Originally Posted by CorySCline View Post
    So we have ave a math problem that we are arguing on. This started as an argument between two 40 year olds looking through kid's math books. Here is the problem:

    If there is 26 times more caffeine in a normal cup of coffee than in decaf and the total between them is 121.5 Grams of caffiene, how much is in each cup?

    While I have no clue how to solve it, I can verify answers (Thank god my old brain retains that ). My logic says that:
    Decaf + Regular = 121.5
    Decaf * 26 = Normal

    He is trying to tell me that Decaf = 4.67 and Caffien = 116.82. Rounded of course.

    I can tell this is wrong because while Decaf + Regular is true, Decaf * 26 is not.

    How can I prove him wrong here?



    Thanks!
    Maybe the fact that, like you said, Decaf x 26 is wrong...
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  3. #3
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    Re: Old guys arguin over math from long ago

    Yes. However, he is dense. He does not understand my logic. How do i solve the problem properly to show him the correct answer?
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    Re: Old guys arguin over math from long ago

    Quote Originally Posted by CorySCline View Post
    Yes. However, he is dense. He does not understand my logic. How do i solve the problem properly to show him the correct answer?
    Assuming that you are using the words "normal" and "regular" for the same thing...

    \displaystyle \begin{align*} d + r &= 121.5 \\ 26d &= r \\ \textrm{Substitute the second equation into the first} \\ d + 26d &= 121.5 \\ 27d &= 121.5 \\ d &= 4.5 \\ \textrm{Substitute this answer into the second equation} \\ 26\cdot 4.5 &= r \\ 117 &= r \end{align*}

    So with this working, and showing him that the numbers work in both equations, you should be able to convince him...
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  5. #5
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    Re: Old guys arguin over math from long ago

    Awesome ...He gets it now lol.. Thanks for your time
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