document.write( "Question 926006: How do I dilute a 70% peroxide solution to a 35% solution then to a 3.5% solution
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Algebra.Com's Answer #561908 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "First part of question:\r\n" );
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\n" ); document.write( "How do I dilute a 70% peroxide solution to a 35% solution...
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document.write( "250 ml of the 70% solution contains 175 ml of peroxide and the rest water.\r\n" );
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document.write( "(That's because 70% of 250 ml is 175)\r\n" );
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document.write( "We will now add x ml of water.\r\n" );
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document.write( "Then there will still be only 175 ml of peroxide but there will be a total of\r\n" );
document.write( "250+x ml of liquid altogether.\r\n" );
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document.write( "We therefore want the 175 ml of peroxide to equal 35% of the total 250+x ml \r\n" );
document.write( "of liquid, so\r\n" );
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document.write( "                  175 = 0.35(250+x)\r\n" );
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document.write( "Solve that and get x = 250 ml of water is to be added. \r\n" );
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document.write( "So the answer to the first part of the problem is \r\n" );
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document.write( "\"Add 250 ml of water\".\r\n" );
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document.write( "{Note: It makes sense that we would have to double the amount of liquid \r\n" );
document.write( "since 35% is exactly half of 70%. Therefore we could have reasoned out \r\n" );
document.write( "that the answer would be 250 ml of water without doing any algebra, since \r\n" );
document.write( "we started with 250 ml of solution and needed to double it to make it half\r\n" );
document.write( "strength!]\r\n" );
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document.write( "Second part of question:\r\n" );
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\n" ); document.write( "...then to a 3.5% solution...
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document.write( "Now that we have added 250 ml of water to the 250 ml of solution, we now\r\n" );
document.write( "have 500 ml of solution of which still only 175 ml is peroxide and the rest\r\n" );
document.write( "water.\r\n" );
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document.write( "We will now add y ml of water.\r\n" );
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document.write( "Now there will still be only 175 ml of peroxide but there will be a total \r\n" );
document.write( "of 500+y ml of liquid altogether.\r\n" );
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document.write( "We therefore want the 175 ml of peroxide to equal 3.5% of the total 500+y\r\n" );
document.write( "of liquid, so\r\n" );
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document.write( "                  175 = 0.035(500+x)\r\n" );
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document.write( "Solve that and get x = 4500 ml of water is to be added.\r\n" );
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document.write( "So the answer to the second part of the problem is: \r\n" );
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document.write( "\"Add 4500 ml more water\".  (You could call that 4.5 liters of water.)\r\n" );
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document.write( "Edwin
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