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Math Help - simultaneous equation problem solving

  1. #1
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    simultaneous equation problem solving

    John's mother is 5 times as old as John is. Three years ago, she was 9 times his age. What are their present ages?
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  2. #2
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    Have a think.

    Let John's age be x

    His mother's age will then be 5x

    So three years ago she was nine times his age...

    5x-3 = 9(x-3)

    The -3 on the left side represents 3 years ago, you also have to do it on his mother's age. Since she is nine times the age just multiply the whole side by 9.
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  3. #3
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    Thanks jgv115,

    So is it:

    5x-3=9(x-3)
    5x-3=9x-27
    27-3=9x-5x
    24=4x
    6=x
    So John would be 6 years old and his mum would be 6x5=30
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  4. #4
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    Indeed.
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  5. #5
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    Thank you very, very much "jgv115".

    I will no doubt have many more simple questions over the next 10months.
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