document.write( "Question 511301: A radiator contains 13 quarts of fluid, 20% of which is antifreeze. How much fluid should be drained and replaced with pure antifreeze so that the new mixture is 50% antifreeze? (Round your answer to two decimal places.)
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Algebra.Com's Answer #342148 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
The key is: you start with 13 quarts and you end up with
\n" ); document.write( "13 quarts.
\n" ); document.write( "Let $\"+x+\"$ = quarts of fluid to be drained
\n" ); document.write( "and replaced with pure antifreeze
\n" ); document.write( "given:
\n" ); document.write( " $\"+.2%2A13+=+2.6+\"$ quarts of original antifreeze
\n" ); document.write( " $\"+.2x+\"$ = quarts of antifreeze drained off
\n" ); document.write( "-----------------
\n" ); document.write( " $\"+%28+2.6+-+.2x+%2B+x+%29+%2F+13+=+.5+\"$
\n" ); document.write( " $\"+%28+2.6+%2B+.8x+%29+%2F+13+=+.5+\"$
\n" ); document.write( " $\"+2.6+%2B+.8x+=+6.5+\"$
\n" ); document.write( " $\"+.8x+=+3.9+\"$
\n" ); document.write( " $\"+x+=+4.875+\"$
\n" ); document.write( "4.88 quarts of fluid should be drained and replaced with pure antifreeze
\n" ); document.write( "check:
\n" ); document.write( " $\"+%28+2.6+-+.2x+%2B+x+%29+%2F+13+=+.5+\"$
\n" ); document.write( " $\"+%28+2.6+%2B+.8%2A4.875+%29+%2F+13+=+.5+\"$
\n" ); document.write( " $\"+%28+2.6+%2B+3.9+%29+%2F+13+=+.5+\"$
\n" ); document.write( " $\"+6.5+%2F+13+=+.5+\"$
\n" ); document.write( " $\"+6.5+=+6.5+\"$
\n" ); document.write( "OK \n" ); document.write( "

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