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Math Help - the mean

  1. #1
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    the mean

    Hi, this is my question:

    The mean age of 5 friends is 36.
    Another person joins the group and the mean age drops to 35.
    how old is the 6th person?

    im not sure how to work this out so could someone show me please?
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  2. #2
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    Quote Originally Posted by andyboy179 View Post
    Hi, this is my question:

    The mean age of 5 friends is 36.
    Another person joins the group and the mean age drops to 35.
    how old is the 6th person?

    im not sure how to work this out so could someone show me please?
    If you denote by 'S' the sum of ages of the 5 friends and by 'a' the age of 6th person, you arrive to these two equations:
    S/5=36
    (S+a)/6=35

    Can you solve them?
    [The answer should be 30.]
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  3. #3
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    Bristol, England
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    Quote Originally Posted by kompik View Post
    If you denote by 'S' the sum of ages of the 5 friends and by 'a' the age of 6th person, you arrive to these two equations:
    S/5=36
    (S+a)/6=35
    Can you solve them?
    [The answer should be 30.]
    i don't understand that with the S and the A, can you explain it and easier way?

    would this work:
    36/6 = 6
    6X5=30?
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