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Math Help - math prroblem

  1. #1
    Junior Member
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    Smile math prroblem

    please help me solve this
    sally bought three cholate bars and a pack of gum and paid $1.75. Jake bought two cholate bars and four packs of gum and paid $2.00. Find the cost of a chocolate bar and the cost of a pack of gum
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  2. #2
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    Hello, lizard4!

    This is a very basic problem with a system of equations.
    Assuming you're new at this, I'll baby-step through it.


    Sally bought three chocolate bars and a pack of gum and paid $1.75.
    Jake bought two chocolate bars and four packs of gum and paid $2.00.
    Find the cost of a chocolate bar and the cost of a pack of gum

    Let C = cost of a chocolate bar.
    Let G = cost of a pack of bum.

    Sally bought 3 chocolate bars at C cents each.
    . . They cost her: . 3C cents.
    She bought 1 pack of gum at G cents each.
    . . This cost her: . G cents.
    So she spent: .3C + G[/tex] cents.
    . . But we are told that she spent 175 cents.
    There is one equation: . 3C + G \:=\:175 .[1]

    Jake bought two chocolate bars at C cents each.
    . . This cost him: .[ 2C cents.
    He bought 4 packs of gum at G cents each.
    . . This cost him: . 4G cents.
    So he spent: . 2C + 4G cents.
    . . But we are told that he spent 200 cents.
    There is another equation: . 2C + 4G \:=\:200 .[2]

    Solve the system of equations: . \begin{array}{cccc} 3C +G & = & 175 & [1] \\ 2C + 4G & = & 200 & [2]\end{array}

    Multiply [1] by -4: . \text{-}12C - 4G \:=\:\text{-}700
    . . . . . . .Add [2]: . . 2C + 4G \:=\:\; 200

    And we get: . -10C \:=\:-500\quad\Rightarrow\quad\boxed{ C \,= \,50}

    Substitute into [1]: . 3(50) + G \:=\:175\quad\Rightarrow\quad\boxed{ G \,=\,25}


    Therefore: a chocolate bar costs 50 and a pack of gum costs 25.

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  3. #3
    Junior Member
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    math

    thankyou
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