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One of the fairfax county mathematics league problem

  1. Apr 14, 2008 #1
    I feel like I can solve this problem easily.. However..
    I can't -_-
    I get three variables and I can get only 2 equations..T.T
    How do you solve this!!
    This question makes me itchy!!

    "If Al gives Liz $10 and Carlo gives Liz $15, then Liz has as much money as Al and Carlo together. Instead, if Al gives Carlo $15 and Liz gives Carlo $8, then Carlo has as much money as Al and Liz together. How many dollars does Al have at the start?"
     
  2. jcsd
  3. Apr 15, 2008 #2
    Well, if I read this question correctly, Al has 48$.
     
  4. Apr 15, 2008 #3

    HallsofIvy

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    You start by naming things: Let A be the amount of money Al has at the start, L the amount of money Liz has, and C be the amount of money Carlo has.

    After Al gives Liz $10, he has A- 10 left. After Carlo gives Liz $15, he has C- 15 left. Liz has L+ 10+ 15= L+ 25. Then "Liz has as much money as Al and Carlo together: L+ 25= A-10+ C- 15. L+ 25= A+ C- 25 or L= A+ C- 50.

    If Al gives Carlo $15, he has A- 15. If Liz gives Carlo $8, she has L- 8. Carlo has, of course, C+ 15+ 8= C+ 23. Then "Carlo has as much money as Al and Liz together: C+ 23= L-8+ A- 15= L+ A- 23: C= L+ A- 46.

    You have the two equations: L= A+ C- 50 and C= L+ A- 46. What do you get if you add the two equations?
     
  5. Apr 15, 2008 #4
    oh!!! I see the L cancels out!!!!!!!!!!!!!!!
    Ah,,, I should have got this problem right.!! T.T
    Anyways thanks, now I can sleep with out anxiety!lol ><
     
  6. Apr 16, 2008 #5

    HallsofIvy

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    Is that Fairfax County, Virginia, U.S.A., by the way?
     
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