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Math Riddle: Many can't solve this simple equation ...

Discussion in 'Other Off-Topic Chat' started by pitbull, Aug 5, 2019.

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x = 8/2(2+2)

  1. x = 16

    11 vote(s)
    73.3%

  2. x = 1

    4 vote(s)
    26.7%

  3. None of that because this is an invalid arithmetic expression.

    0 vote(s)
    0.0%
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  1. pitbull

    pitbull Banned Donor

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    x = 8/2(2+2)

    Can you?
     
    pitbull, Aug 5, 2019
    #1
  2. Hoosier8

    Hoosier8 Well-Known Member Past Donor

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    16

    8/(2(2+2)) = 1
     
    Last edited: Aug 5, 2019
    Hoosier8, Aug 5, 2019
    #2
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  3. Hotdogr

    Hotdogr Well-Known Member Past Donor

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    I come up with the same answer.

    Solve the expression in the parentheses first: 2+2=4

    Solve the expression outside the parentheses next:
    8/2=4

    Then solve the equation:4*4=16.

    x=16
     
    Hotdogr, Aug 5, 2019
    #3
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  4. tecoyah

    tecoyah Well-Known Member Past Donor

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    Alexa agrees.
     
    tecoyah, Aug 5, 2019
    #4
  5. drluggit

    drluggit Well-Known Member

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    I would suggest that it's poorly written. if the construct or the equation looks like this:

    8
    ---------
    2(2=2)

    the answer is 1

    Meaning that 8 is divided by the product of the denominator in this case..
     
    drluggit, Aug 5, 2019
    #5
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  6. perdidochas

    perdidochas Well-Known Member

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    It's a trick question, and it is written (not poorly, but trickily) to cause the conundrum we face. IMHO, the way you wrote it is x = 8/(2(2+2)). The way I read it is 8/2*(2+2) Or 8/2x4 or 4x4 or 16. (working left to right)
     
    perdidochas, Aug 5, 2019
    #6
  7. Ritter

    Ritter Well-Known Member

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    Depends how you arrange the equation.
     
    Ritter, Aug 5, 2019
    #7
  8. Hoosier8

    Hoosier8 Well-Known Member Past Donor

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    What is implied but missing is the times notation though it is still correctly written.

    8/2*(2+2)
     
    Last edited: Aug 5, 2019
    Hoosier8, Aug 5, 2019
    #8
  9. Thedimon

    Thedimon Well-Known Member

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    It’s both 1 and 16.
     
    Thedimon, Aug 8, 2019
    #9
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  10. Blaster3

    Blaster3 Well-Known Member

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    that's very quantum of you ;)
     
    Blaster3, Jan 30, 2020
    #10
  11. Diablo

    Diablo Well-Known Member

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    It's like all of these questions, it's just written poorly.
     
    Diablo, Jan 30, 2020
    #11
  12. Diablo

    Diablo Well-Known Member

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    Don't go and look or the cat will die.....
     
    Diablo, Jan 30, 2020
    #12
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  13. jay runner

    jay runner Banned

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    Math has rules that cannot be broken. The numerator has to be taken as a whole. The denominator has to be taken as a whole.
     
    jay runner, Jan 30, 2020
    #13
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  14. Aleksander Ulyanov

    Aleksander Ulyanov Well-Known Member

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    Downright Catty too.

    I agree sorta, You work from the inside out
     
    Last edited: Jan 30, 2020
    Aleksander Ulyanov, Jan 30, 2020
    #14
  15. Blaster3

    Blaster3 Well-Known Member

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    Last edited: Jan 30, 2020
    Blaster3, Jan 30, 2020
    #15
  16. Aleksander Ulyanov

    Aleksander Ulyanov Well-Known Member

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    Aleksander Ulyanov, Jan 30, 2020
    #16
  17. Thought Criminal

    Thought Criminal Well-Known Member Donor

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    Really?

    X=1

    When I was a kid, that was third-grade.

    I guess this is the result of "new math".
     
    Last edited: Jan 30, 2020
    Thought Criminal, Jan 30, 2020
    #17
  18. Quasar44

    Quasar44 Banned

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    A Jewish 4th grader knows that one lol
     
    Quasar44, Apr 5, 2020
    #18
  19. modernpaladin

    modernpaladin Well-Known Member Past Donor

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    x = 8/2(2+2)
    solve in parenthesis first
    x = 8 ÷ 2 × 4
    solve multiplication next
    x = 8 ÷ 8
    solve division next
    x = 1

    what other way is there to do it?
     
    Last edited: Apr 5, 2020
    modernpaladin, Apr 5, 2020
    #19
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  20. cristiansoldier

    cristiansoldier Well-Known Member

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    BODMAS
     
    cristiansoldier, Apr 5, 2020
    #20
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  21. Grey Matter

    Grey Matter Well-Known Member Donor

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    Can you please rephrase the calc using rpn?

    Is it 2 2 + 8 2 / *

    or is it

    8 2 2 + 2 * /

    ?
     
    Last edited: Apr 29, 2020
    Grey Matter, Apr 29, 2020
    #21
  22. Texan

    Texan Well-Known Member

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    The math problem is a victim of grammar.
     
    Texan, Apr 29, 2020
    #22
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  23. Grey Matter

    Grey Matter Well-Known Member Donor

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    It’s not a valid Excel formula
     
    Grey Matter, Apr 29, 2020
    #23
  24. kazenatsu

    kazenatsu Well-Known Member Past Donor

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    It's not an algebraically valid way of writing it, since it leaves ambiguity. Is the quantity to be multiplied under the denominator, or should it be multiplied by the fraction?

    For linear text writing, a fraction should always be contained within a parenthesis if it is to be multiplied.
    (8/2)(2+2)
    versus
    8/(2(2+2))
     
    Last edited: Apr 30, 2020
    kazenatsu, Apr 30, 2020
    #24
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  25. Pisa

    Pisa Well-Known Member

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    The fraction symbol is just a division sign.

    This is the right way to write the equation:
    8 ÷ 2(2 + 2)

    First solve the parenthesis, then the division, then the multiplication.

    8 ÷ 2(2 + 2)=16.

    If the multiplication was to be solved before the division, it would have been written like this:
    8 ÷ [2(2 + 2)]
     
    Pisa, Apr 30, 2020
    #25
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