document.write( "Question 400108: The radiator in a car is filled with a solution of 60
\n" ); document.write( "per cent antifreeze and 40 per cent water. The manufacturer of
\n" ); document.write( "the antifreeze suggests that for summer driving, optimal cooling
\n" ); document.write( "of the engine is obtained with only 50 per cent antifreeze. If
\n" ); document.write( "the capacity of the raditor is 4.2 liters, how much coolant (in
\n" ); document.write( "liters) must be drained and replaced with pure water to reduce
\n" ); document.write( "the antifreeze concentration to 50 per cent \n" ); document.write( "
Algebra.Com's Answer #283313 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
The radiator in a car is filled with a solution of 60
\n" ); document.write( "per cent antifreeze and 40 per cent water. The manufacturer of
\n" ); document.write( "the antifreeze suggests that for summer driving, optimal cooling
\n" ); document.write( "of the engine is obtained with only 50 per cent antifreeze. If
\n" ); document.write( "the capacity of the raditor is 4.2 liters, how much coolant (in
\n" ); document.write( "liters) must be drained and replaced with pure water to reduce
\n" ); document.write( "the antifreeze concentration to 50 per cent
\n" ); document.write( "----
\n" ); document.write( "Equation:
\n" ); document.write( "acid - acid + acid = acid
\n" ); document.write( "0.60*4.2 - 0.60x + 0x = 0.5*4.2
\n" ); document.write( "-----
\n" ); document.write( "Multiply thru by 100 to get:
\n" ); document.write( "60*4.2 - 60x + 0 = 50*4.2
\n" ); document.write( "-60x = -10*4.2
\n" ); document.write( "x = 0.7 liters (amt. of coolant that must be replaced)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
\n" ); document.write( "============ \n" ); document.write( "
\n" );