document.write( "Question 532301: Automotive maintenance. The radiator in Natalie’s car contains 6.3 L of antifreeze and water. This mixture is 30% antifreeze. How much of this mixture should she drain and replace with pure antifreeze so that there will be a mixture of 50% antifreeze? \n" ); document.write( "

Algebra.Com's Answer #350793 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"x\"$ = liters of mixture she should
\n" ); document.write( "drain and replace with pure antifreeze
\n" ); document.write( "-----------
\n" ); document.write( "given:
\n" ); document.write( " $\"+.3x+\"$ = liters of pure antifreeze that
\n" ); document.write( "she drains off
\n" ); document.write( " $\"+.3%2A%28+6.3+-+x+%29+\"$ = pure antifreeze left after
\n" ); document.write( "she drains off $\"+x+\"$ liters of mixture
\n" ); document.write( "-----------
\n" ); document.write( " $\"+%28+.3%2A%28+6.3+-+x+%29+%2B+x+%29+%2F+6.3+=+.5+\"$
\n" ); document.write( " $\"+%28+1.89+-+.3x+%2B+x+%29+%2F+6.3+=+.5+\"$
\n" ); document.write( " $\"+1.89+%2B+.7x+=+.5%2A+6.3+\"$
\n" ); document.write( " $\"+.7x+=+3.15+-+1.89+\"$
\n" ); document.write( " $\"+.7x+=+1.26+\"$
\n" ); document.write( " $\"+x+=+1.8+\"$
\n" ); document.write( "She must drain off 1.8 liters and replace with pure antifreeze
\n" ); document.write( "check:
\n" ); document.write( " $\"+%28+.3%2A%28+6.3+-+x+%29+%2B+x+%29+%2F+6.3+=+.5+\"$
\n" ); document.write( " $\"+%28+.3%2A%28+6.3+-+1.8+%29+%2B+1.8+%29+%2F+6.3+=+.5+\"$
\n" ); document.write( " $\"+%28+.3%2A4.5+%2B+1.8+%29+%2F+6.3+=+.5+%7D%7D%0D%0A%7B%7B%7B++1.35+%2B+1.8++=+.5%2A6.3+\"$
\n" ); document.write( " $\"+3.15+=+3.15+\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );