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Math Help - Help setting up equastion for Solving Systems? Word Question

  1. #1
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    Help setting up equastion for Solving Systems? Word Question

    A biologist has a 40% solution and a 10% solution, how many cubic centimeters of each should be mixed to obtain a 25cc of a 28% solution?

    I tried to set it up as

    28=40x+10y but I realize I don';t have the 25cc accounted for...
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  2. #2
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by emximer View Post
    A biologist has a 40% solution and a 10% solution, how many cubic centimeters of each should be mixed to obtain a 25cc of a 28% solution?

    I tried to set it up as

    28=40x+10y but I realize I don';t have the 25cc accounted for...
    Let x be the amount of the 40% solution, and y be the amount of the 10% solution in the mixture, both measured in cc's. then,

    x + y = 25 .................the total must be 25

    and

    0.4x + 0.1y = 0.28 ..................the percentages must add up to 28%

    those are your two equations.
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  3. #3
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    thank you, but for some reason I still can't solve the equation, I just get x=7.4 and y= 17.6, which doesn't really make sense as it doesn't solve both equations....
    further help please, as I have 3 more problems just like this



    thank you!
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