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MATHS

  • 11-11-2014 6:58pm
    #1
    Registered Users Posts: 5 rebels_cork


    The area of a rectangle is 44cm2. if one side is 3cm longer than the other, find the length of the shorter side? Anyone know this??


Comments

  • Registered Users Posts: 603 ✭✭✭ eoins23456


    (x)*(x+3)=44
    x^2+3x-44=0 then solve for x


  • Registered Users Posts: 4 AlexTheLion


    Given two unlabelled teams of n members each, if two sets of n are redrawn at random, what is the probability of k members changing teams?


  • Registered Users Posts: 4 AlexTheLion


    Given two unlabelled teams of n members each, if two sets of n are redrawn at random, what is the probability of k members changing teams?


  • Registered Users Posts: 176 ✭✭ Blackpanther95


    My guess: number of combos: 2nCn . number of combos with n members changing (nCk)^2
    From the first group pick the k members then do the same for the second group. I might however be double counting.
    Then you just divide the second term by the first one given.


  • Registered Users Posts: 3 Keelsean


    Side X x Y = Area so
    X x (X+3) = 44
    or more often written
    X(X+3) = 44 so multiply out left side getting to the stage where Eoin(above) is

    X^2 + 3X – 44 = 0 reads as X squared + 3X = 44 ... now we bring 44 to other side of = sign leaving 0 there so
    if we factorise

    X^2 + 3X – 44 = 0 factorise so factors of 44 that give 3 ... one of the factors equals Zero as the only way to get a zero
    when multiplying is if one amount is zero to start

    Problem is that 44 doesn't factorise cleanly to whole numbers that will leave 3 when added or subtracted so this is obviously an honours JC level question where you'll need to use the Quadratic Formula to fully solve.
    This will be too confusing to simply write out here but if you need it taken the rest of the way then just let me know by reply


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  • Keelsean wrote: »
    Side X x Y = Area so
    X x (X+3) = 44
    or more often written
    X(X+3) = 44 so multiply out left side getting to the stage where Eoin(above) is

    X^2 + 3X – 44 = 0 reads as X squared + 3X = 44 ... now we bring 44 to other side of = sign leaving 0 there so
    if we factorise

    X^2 + 3X – 44 = 0 factorise so factors of 44 that give 3 ... one of the factors equals Zero as the only way to get a zero
    when multiplying is if one amount is zero to start

    Problem is that 44 doesn't factorise cleanly to whole numbers that will leave 3 when added or subtracted so this is obviously an honours JC level question where you'll need to use the Quadratic Formula to fully solve.
    This will be too confusing to simply write out here but if you need it taken the rest of the way then just let me know by reply

    I'm sure OP managed to figure it out in the seven years since.


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