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50%? :d

  1. Dec 1, 2003 #1
    A question, kind a tricky problem if you think it's easy.

    [tex]xv^{2}z^{3}[/tex]

    if the values of x, v, and z are each decreased by 50 percent, then the value of the expression is decreased by what percentage?

    [tex]\frac{(x(1-0.5)v(1-0.5)^{2}z(1-0.5)^{3})}{xv^{2}z^{3}}[/tex]

    Wonder if that's how you do it...
     
    Last edited: Dec 1, 2003
  2. jcsd
  3. Dec 1, 2003 #2

    HallsofIvy

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    I don't see why you have divided by xv2z3.

    Here's how I would do this: x decreased by 50% is (as you have it)
    x(1- .5) which is then 0.5 x or x/2. Similarly v is reduce to v/2 and z is reduced to z/2.

    xv2z3 is reduced to (x/2)(v/2)2(z/2)3= (xv2z3)/(2*4*8)= (xv2z3)/64. In other words xv2z3 is reduce to 1/64 of it's value.

    (Oh, THAT'S why you divided by xv2z3- to get only the multiplier! Yes, you are correct!)

    Reducing it to 1/64 is the same as reducing it by 63/64 which is 98.4375%.
     
    Last edited: Dec 1, 2003
  4. Dec 1, 2003 #3

    ahrkron

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    Just be careful with the parentheses:

    [tex]\frac{x(1-0.5)(v(1-0.5))^{2}(z(1-0.5))^{3}}{xv^2z^3}[/tex]
     
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