SOLUTION: A certain automobile cooling system contains 11.0 liters of coolant that is 15% antifreeze. How man liters of mixture must be removed so that, when it is replaced with pure antifre

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: A certain automobile cooling system contains 11.0 liters of coolant that is 15% antifreeze. How man liters of mixture must be removed so that, when it is replaced with pure antifre      Log On

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Question 793100: A certain automobile cooling system contains 11.0 liters of coolant that is 15% antifreeze. How man liters of mixture must be removed so that, when it is replaced with pure antifreeze, a mixture of 25% antifreeze will result
Found 2 solutions by stanbon, josmiceli:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
A certain automobile cooling system contains 11.0 liters of coolant that is 15% antifreeze. How man liters of mixture must be removed so that, when it is replaced with pure antifreeze, a mixture of 25% antifreeze will result.
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Equation:
anti - anti + anti = anti
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0.15*11 - 0.15x + 1*x = 0.25*11
-----------------
15*11 - 15x + 100x = 25*11
85x = 10*11
x = 1.2941 liters (amt of antifreeze to remove and replace)
Cheers,
Stan H.
=============

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
L:et +x+ = liters of mixture to be removed
and replaced with pure antifreeze
----------------------------
+.15x+ = liters of pure antifreeze
in +x+ liters of mixture
-----------------------
+.15%2A11+=+1.65+ liters of pure antifreeze in
original mixture
-------------
Note that you end up with the same number
of liters that you started with
-------------
+%28+1.65+-+.15x+%2B+x+%29+%2F+11+=+.25+
+1.65+%2B+.85x+=+.25%2A11+
+.85x+=+2.75+-+1.65+
+.85x+=+1.1++
+x+=+1.294+ liters
-------------------
check answer:
+%28+1.65+-+.15%2A1.294+%2B+1.294+%29+%2F+11+=+.25+
+%28+1.65+-+.194+%2B+1.294+%29+%2F+11+=+.25+
+2.75+%2F+11+=+.25+
+2.75+=+2.75+
OK