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The pole in a lake

  1. Jan 10, 2007 #1
    The pole in a lake!!

    There is a pole in a lake. One-half of the pole is in the ground, another one-third of it is covered by water, and 12 ft is out of the water. What is the total length of the pole in 'ft'?:bugeye:
     
  2. jcsd
  3. Jan 10, 2007 #2

    Hootenanny

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    72ft

    (damn this 10 character minimum limit)
     
  4. Jan 10, 2007 #3
    How is that this is posted under the Brain Teasers section?
     
  5. Jan 10, 2007 #4
    72ft is correct
    Solution:

    Fraction of pole in the ground = 1/2
    Fraction of pole covered by water = 1/3
    Fraction of pole in the ground and covered by water = 1/2 + 1/3 = (3 + 2)/6 = 5/6
    Fraction of pole out of water = 1 - 5/6 = 1/6
    Thus, one-sixth of the pole (out of water) is 12 ft.
    So, total length of pole = 72 ft.

    It may be noted that:
    Length of pole in the ground = 72/2 = 36 ft.
    Length of pole covered by water = 72/3 = 24 ft.
    Length of pole out of water = 12 ft.


    The problem may also be solved by setting up the following equation: x/2 + x/3 + 12 = x
    where x denotes the total length of the pole in ft.
    The equation may be solved as shown below.
    5x/6 + 12 = x
    12 = x - 5x/6 = x/6
    x/6 = 12 or x = 72.
     
  6. Jan 10, 2007 #5
    True, these questions from a jr.high quiz aren't really brain teasers powergirl....
     
  7. Jan 10, 2007 #6
    ooo...sorry
     
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