Question 795720:  "A chemist needs 80 milliliters of a 27% solution but has only  17% and 33% solutions available. find how many milliliters of each that should be mixed to get the desired solution."
 
If you could please explain to me how i can find the equations, variables, essentially how to solve it i am completely at a loss, i have not idea how to find the equations/variables to be modeled by a system. Please and Thank You! 
--Ashley 
 Answer by MathTherapy(10557)      (Show Source): 
You can  put this solution on YOUR website! "A chemist needs 80 milliliters of a 27% solution but has only  17% and 33% solutions available. find how many milliliters of each that should be mixed to get the desired solution."
 
If you could please explain to me how i can find the equations, variables, essentially how to solve it i am completely at a loss, i have not idea how to find the equations/variables to be modeled by a system. Please and Thank You! 
--Ashley
 
 
Let amount of 17% solution to be added be S 
Since the mixture will sum to 80 mL, then amount of 33% solution to be added = 80  S
 
 
Therefore, .17S + .33(80  S) = .27(S + 80  S) 
.17S + 26.4 - .33S = 21.6  
.17S - .33S = 21.6  26.4  
- .16S = - 4.8
 
 
S, or amount of 17% solution to be added =  , or   mL
 
 
Amount of 33% solution to be added = 80  30, or   mL
 
 
You can do the check!! 
 
 
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