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Math Help - following numbers have a mean of 5, find the value of x

  1. #1
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    following numbers have a mean of 5, find the value of x

    Hi I need your help. I can't work out how to find X. I know how to find the cofficient of the variation if I knew what X was.

    Thanks
    If the following numbers have a mean of 5, find the value of x and find the coefficient of variation

    5 x 2 x 9 11 1
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  2. #2
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    Re: following numbers have a mean of 5, find the value of x

    write down the formula for the mean:

    mean = 5 = \frac{5+x+2+x+9+11+1}{7}
    5 = \frac{2x  + 28}{7}
    5 = \frac{2x}{7}  + \frac{28}{7}
    solve for x

    Once you have x, you can compue the coefficient of variation manually.
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  3. #3
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    Re: following numbers have a mean of 5, find the value of x

    \frac{5+x+2+x+9+11+1}{7} = 5

    then

    \frac{2x+5+2+9+11+1}{7} = 5

    Can you find it now?
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  4. #4
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    Re: following numbers have a mean of 5, find the value of x

    No I can't work out what 2x is??
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  5. #5
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    Re: following numbers have a mean of 5, find the value of x

    \frac{2x+5+2+9+11+1}{7} = 5

    From here, times both sides by 7, then subtract 5+2+9+11+1 from both sides, then divde both sides by 2.
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  6. #6
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    Re: following numbers have a mean of 5, find the value of x

    I'm lost could you show me how that works?
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  7. #7
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    Re: following numbers have a mean of 5, find the value of x

    [How do I solve X?

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  8. #8
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    Re: following numbers have a mean of 5, find the value of x

    Follow these 3 steps.

    1. take 28/7 from both sides of the equation
    2. Multiply both sides of the equation by 7
    3. Divide both sides of the equation by 2
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