Art of Problem Solving: 2016 AMC 10 A #23 / AMC 12 A #20

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  • Опубликовано: 24 окт 2024

Комментарии • 13

  • @jackjin3748
    @jackjin3748 5 лет назад +3

    I loooove the way Deven does this - making the correct solution so intuitively acceptable (and also replicable in future problems).

  • @richardxu7251
    @richardxu7251 8 лет назад +4

    For those who are morbidly curious in the end if there's other symbol that satisfy diamond:
    Let # be diamond. Note that (a#b)*b=a#(b#b)=a#1=a, so a#b=a/b. Therefore, # is division.

    • @M_Chen333
      @M_Chen333 6 лет назад +1

      He mentions that it's division in the video...

  • @DatHamTho
    @DatHamTho 8 лет назад +19

    u changed a lot Richard
    (a joke)

  • @BillPark-ey6ih
    @BillPark-ey6ih 5 лет назад

    I have a more simple solution here :)
    let's say the diamond notation is @.
    From a@a=1, it can be either (a * 1/a) or (a - a), and we can predict that a@b = a*1/b or a - b
    However, a@(b@c) = (a@b)*c implies that a@a is (a*1/a) because there is multiplication of c, not addition or subtraction.
    If we calculate a@(b@c) with a@b = a*1/b, it works.
    With simple calculation with 2016@(6@x)=100, we can solve the problem.
    Also, if you just think, the problem-producer(?) will not make the notation too complicated because then he should add more limitations to the problems exponentially.

  • @pleabargain
    @pleabargain 8 лет назад

    Let diamond represent any equation and what do you have? More complex algebra or something else by another name? I do like the idea of just plugging in a simple variable, 1 in this case, to at least start somewhere...

  • @eric4334
    @eric4334 Год назад

    WHERE IS RICHARD RUSCEHYTPT%ROG

  • @M_Chen333
    @M_Chen333 7 лет назад

    Alternatively, he could've factored a 6 out of 2016#6. (#=diamond) Then it turns into 6(336#1)=600/x. Divide by 6 and you get
    336=100/x, which simplifies into x=100/336, which is 25/84.

    • @sss-ol3dl
      @sss-ol3dl 6 лет назад

      You can't assume that you can factor like that.

    • @f5673-t1h
      @f5673-t1h 4 года назад

      That's wrong. We know diamond is division, so if you had like 2#2, that 2/2 = 1. But you're assuming you can do 2#2 = 2(1#1), which would equal 2, not 1.
      You made an assumption that was not stated and could not be concluded from the given properties.

  • @theevilmathematician
    @theevilmathematician 2 года назад

    this is very misplaced for a #23

  • @OO-fg4cr
    @OO-fg4cr 8 лет назад +2

    Srsly, a 5 minute video on this joke problem? Anyone could see that diamond is a binary operations so there aren't that many choices. The obvious one is division and it satisfies the first premise so it's division. This is a 20 second problem... And also what happened to you Richard ;_;.

    • @Enderman-en3dv
      @Enderman-en3dv 6 лет назад +2

      Did you not even listen to him when he explained what a binary operation is, or are you just that stupid