SOLUTION: a chemist needs 140 milliliters of a 36% solution. How many milliliters of a 30% solution and 44% solution are needed to obtain desired solution? that is the problem i know there i

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Question 391425: a chemist needs 140 milliliters of a 36% solution. How many milliliters of a 30% solution and 44% solution are needed to obtain desired solution? that is the problem i know there is a trick to doing these solution problems i just don't remember. i tried the equation 30x+44y=140(36) but it does not figure.
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi, 

chemist needs 140 milliliters of a 36% solution    

Let x and (140ml-x) represent represent the amounts of the 44% and 30% respectively

Question states***

 Mixing to form the 36% solution

 .44x + .30(140ml-x)= .36*140ml

    .14x = .06*140ml

        x = .06*140ml/.14 

        x = 60ml, the amount of the 44 % solution.  80ml the amount of 30% solution



CHECKING our Answer

  .44*60ml + .30*80ml = 26.4ml + 24ml = .36*140ml   = 50.4ml