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Jak and Jill Maths problem

  1. Feb 26, 2009 #1
    when Jill was one third as old as Jack is now, Jack was one year older than Jill was when Jack was half as old as Jill is now. Jill is 22, how old is her brother Jack?

    this is irritating me and i am set to waste a lot of time unless i find out how its worked out soon.
     
  2. jcsd
  3. Feb 26, 2009 #2
    Maybe writing it like this might help
    Jill(to)=22
    Jill(Jack(to)/3)+1=Jack(Jill(to)/2)

    Jill(t)=22+(t-to)

    Therefore

    22+(Jack(to/3))-to+1=Jack(11)

    Jack=Jack(to)+(t-to)

    Solve for Jack(to)
     
  4. Feb 28, 2009 #3
    Hey there,

    John Creighto has knocked it on the head. However, in words, consider the sentences separately with respect to how old they used to be at a simple point in time, e.g. when Jill was younger (a third of Jack now), what is the equation that gives the age of Jack at that same point in time. Then you can equate the two.

    The Bob
     
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