document.write( "Question 66306: A 6-quart cooling system is checked and found to be filled with a solution that is 20% antifreeze. The desired strength of the solution is 60 % antifreeze. How many quarts of solution need to be drained and replaced with pure antifreeze to reach the desired strength? \n" ); document.write( "
Algebra.Com's Answer #47032 by funmath(2933)\"\" \"About 
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A 6-quart cooling system is checked and found to be filled with a solution that is 20% antifreeze. The desired strength of the solution is 60 % antifreeze. How many quarts of solution need to be drained and replaced with pure antifreeze to reach the desired strength?
\n" ); document.write( "You start with 6 quarts of 20% antifreeze .20*(6)=1.2
\n" ); document.write( "You take out (x amount) -.20x=-.2x
\n" ); document.write( "You put in 100% of (the same x amount) +1.00x=+x
\n" ); document.write( "You want 6 quarts of 60% antifreeze .60(6)=3.6
\n" ); document.write( "The problem to solve:
\n" ); document.write( ".20(6)-.20x+1.00x=.60(6)
\n" ); document.write( "1.2-.2x+x=3.6
\n" ); document.write( "1.2+.8x=3.6
\n" ); document.write( "1.2-1.2+.8x=3.6-1.2
\n" ); document.write( ".8x=2.4
\n" ); document.write( ".8x/.8=2.4/.8
\n" ); document.write( "x=3 qts\r
\n" ); document.write( "\n" ); document.write( "Happy Calculating!!!
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