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Child in a family has at least 4sis and 2bros.

  1. Aug 17, 2009 #1
    1. The problem statement, all variables and given/known data

    Every child in a family has at least 4sis and 2bros. What is the least no. of children in the family?

    2. Relevant equations

    every child has 4 sis and 2 bros.

    3. The attempt at a solution

    so, atleast 6+1 children.

    so answer, i guess shud b seven??
    can some1 confirm this?? answer is quiet visible i guess.
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Aug 17, 2009 #2

    kuruman

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    I am not sure this question belongs here, but anyway, if the correct answer is seven, how many boys should there be and how many girls? Pretend that you are one of these boys, do you have two brothers and four sisters? Now pretend you are one of the girls. Do you have two brothers and four sisters? Be sure not to count yourself.
     
  4. Aug 17, 2009 #3
    yeah, thatz wat is bugging me.

    question states a child and does not mentions the sex.
     
  5. Aug 17, 2009 #4

    kuruman

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    So if there are seven children does it work with 6 girls + 1 boy? No. Does it work with 5 girls + 2 boys or how about 4 girls + 3 boys? Try it like I said with all the possible splits of seven and see if any of them works.
     
  6. Aug 17, 2009 #5
    the only possible combinations are:

    4G+2B+1G = 7 CHILDREN
    (internally, each boy wont have 2brothers and sister will increase to 5)
    4G+2B+1B = 7 CHILDREN.

    If we consider 1/4G+1/2B ??
    But this time atleast 4 sis and 2 bro rqmnt will b completed.
    each child will have atleast 4 sis and 2 bro.
    so, least children will b 1G+4G+2B+1B= 8 children!!

    i think thatz it.
     
    Last edited: Aug 17, 2009
  7. Aug 17, 2009 #6

    kuruman

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    1G+4G+2B+1B is not 10 children. Perhaps you need to use a calculator.
     
  8. Aug 17, 2009 #7
    is it correct now??
     
  9. Aug 17, 2009 #8
    Yup, looks correct; 5 girls and 3 boys must be the minimum criteria fufilled.
     
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