document.write( "Question 450189: A mechanic nees a radiator to have a 40% antifreeze solution. The radiator currently is filled with 4 gallons of a 25% antifreeze solution. How much of the antifreeze mixture should be drained from the car if the mechanic replaces it with pur antifreeze? \n" ); document.write( "
Algebra.Com's Answer #309741 by ankor@dixie-net.com(22740)\"\" \"About 
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A mechanic needs a radiator to have a 40% antifreeze solution.
\n" ); document.write( " The radiator currently is filled with 4 gallons of a 25% antifreeze solution.
\n" ); document.write( " How much of the antifreeze mixture should be drained from the car if the
\n" ); document.write( " mechanic replaces it with pure antifreeze?
\n" ); document.write( ":
\n" ); document.write( "Let x = amt to be drained, and amt of pure antifreeze to be added
\n" ); document.write( ":
\n" ); document.write( ".25(4-x) + x = .40(4)
\n" ); document.write( "1 - .25x + x = 1.6
\n" ); document.write( "-.25x + x = 1.6 - 1
\n" ); document.write( ".75x = .6
\n" ); document.write( "x = \".6%2F.75\"
\n" ); document.write( "x = .8 gal removed and .8 gal of pure antifreeze added
\n" ); document.write( ";
\n" ); document.write( ":
\n" ); document.write( "Check solution in original equation
\n" ); document.write( ".25(4-.8) + .8 = .4(4)
\n" ); document.write( ".25(3.2) + .8 = 1.6 \n" ); document.write( "
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