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  1. #1
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    Question age related question

    Is this question right or some information is missing in it ?

    In 5 years time father will be 3 times as old as his son. four years ago father was 6 times as old as his son.

    Find their present age ?

    Can anyone help me solve it if its correct
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  2. #2
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    skeeter's Avatar
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    Re: age related question

    Quote Originally Posted by haftakhan View Post
    Is this question right or some information is missing in it ?

    In 5 years time father will be 3 times as old as his son. four years ago father was 6 times as old as his son.

    Find their present age ?

    Can anyone help me solve it if its correct
    let f = father's present age

    s = son's present age

    In 5 years time father will be 3 times as old as his son
    f + 5 = 3(s + 5)

    four years ago father was 6 times as old as his son
    f - 4 = 6(s - 4)

    yes, the system of equations has a unique solution.
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  3. #3
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    e^(i*pi)'s Avatar
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    Re: age related question

    Quote Originally Posted by haftakhan View Post
    Is this question right or some information is missing in it ?

    In 5 years time father will be 3 times as old as his son. four years ago father was 6 times as old as his son.

    Find their present age ?

    Can anyone help me solve it if its correct
    With these problems it's always good to write down what you know using variables. Let the father's age now be x and the son's age now be y.
    Now we can write a number of equations based on what we're told:

    In 5 years time father will be 3 times as old as his son: x+5 = 3(y+5)

    four years ago father was 6 times as old as his son: x-4 = 6(y-4)

    You now have a pair of simultaneous equations in x and y so you can solve it. In this case it would be easier to use elimination by taking the second equation from the first
    Last edited by e^(i*pi); December 11th 2011 at 08:26 AM. Reason: changed hyphen to colon
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