document.write( "Question 1175630: How much water should be added to 20mL of 18% alcohol solution to reduce the concentration to 10%?
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Algebra.Com's Answer #801271 by ikleyn(52790) $\"\"$ $\"About$

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document.write( "     = 0.1\r\n" );
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document.write( "    3.6                    = 0.1*(20+w)\r\n" );
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document.write( "    3.6                    = 2 + 0.1w\r\n" );
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document.write( "    3.6 - 2                = 0.1w\r\n" );
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document.write( "    1.6                    = 0.1w\r\n" );
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document.write( "      w                    =  = 16.\r\n" );
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document.write( "ANSWER.  16 mL of water should be added.\r\n" );
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document.write( "CHECK.    =  = 0.1 = 10% concentration.   ! Correct !\r\n" );
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document.write( "    20 mL of the 18% solution contain  0.18*20 = 3.6 mL pure alcohol.\r\n" );
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document.write( "    To have 10% solution, the total volume must be  36 mL;\r\n" );
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document.write( "    hence,  16 = 36-20  milliliters of water must be added.\r\n" );
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