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Posers and Puzzles

Posers and Puzzles

  1. Standard member talzamir
    Art, not a Toil
    29 Dec '11 10:00
    A post-xmas sale promised reductions of price ranging to 30 to 70 percent. Seeing that 30+70 = 100 had me thinking..

    A company increases the price of a product by p%, then reduces it by q% so that p + q = 100. How much is p, if two changes cancel each other out?
  2. Standard member forkedknight
    Defend the Universe
    29 Dec '11 16:21 / 1 edit
    Well
    1 + p has an inverse relation ship with 1 - q if the two cancel each other out, and since p + q = 1, then 1 - q = p:

    (1 + p) * p = 1

    p^2 + p - 1 = 0

    The quadratic formula makes that

    p = -1/2 + sqrt(5)/2 ~= 0.618
  3. Standard member talzamir
    Art, not a Toil
    29 Dec '11 22:34
    Indeed it is. The golden ratio once again.