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Homework Help: Fractions of amounts questions

  1. Aug 29, 2012 #1
    Ok here's the problem.

    2/5 of the children in Year 8 play the piano.
    1/4 of the children in Year 8 play the violin
    No child plays more than one instrument.

    1) Of the children in Year 8. What fraction do not play the piano or the violin?

    Easy i did 1-(2/5+1/4) = 7/20

    There are fewer than 50 children in Year 8.
    1/2 of the children who do not play the piano or the violin play the drums.

    2) How many children are there in Year 8?


    Thanks for your help in advance,

  2. jcsd
  3. Aug 29, 2012 #2


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    Staff: Mentor

    I'm guessing here, but maybe the numbers do not turn out to be a whole number of children except if you get the total number of kids right. Does that help? You can't have a fraction of a kid...
  4. Aug 30, 2012 #3


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    Homework Helper

    So what fraction of the children play the drums?

    If there are N children, home many children play the drums?
    As Berkeman pointed out, only whole number of children can play the drums.

  5. Aug 31, 2012 #4
    The fraction of children playing the drum is 3.5/20 or 7/40...

    Which would make the total number of children in Year 8 to be 40. Is this correct?
    Last edited: Aug 31, 2012
  6. Aug 31, 2012 #5


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    Homework Helper

    Yes. It could be any multiple of 40 to give integer number of children, but the problem said that there are less than 50 children in year 8.

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