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Math Help - problem

  1. #1
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    problem

    The square of Johns age six years ago is equal to her age in six years time. What is his current age?

    Help? Please? :X
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by jimmybob View Post
    The square of Johns age six years ago is equal to her age in six years time. What is his current age?

    Help? Please? :X
    Let John's age be j, then we are told that:

    (j - 6)^2 = j + 6

    simplifying this becomes:

    j^2 - 13 j + 30 = 0

    Which has roots j=10 and j=3, but since for this to work j must be >6, the answer is 10.

    RonL
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