document.write( "Question 1162818: You need 455 mL of a 85% alcohol solution. On hand, you have a 35% alcohol
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Algebra.Com's Answer #786682 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "I'll change the numbers so you'll have to do something other than type them\r\n" );
document.write( "in and get credit for what somebody else did.\r\n" );
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You need 605 mL of a 75% alcohol solution. On hand, you have a 45%
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document.write( "        |How many ml?|Strength| ml of pure alcohol\r\n" );
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document.write( "Solution|     x      | 0.45   |     0.45x\r\n" );
document.write( "Alcohol |     y      | 1.00   |     1.00y\r\n" );
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document.write( "            605        0.75         0.75(605) \r\n" );
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document.write( "The equations come from the first and last columns:\r\n" );
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document.write( "             x + y = 605\r\n" );
document.write( "     0.45x + 1.00y = 0.75(605)\r\n" );
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document.write( "Multiply the second equation through by 100,\r\n" );
document.write( "that is, move the decimal 2 places right on one factor:\r\n" );
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document.write( "             x + y = 605\r\n" );
document.write( "        45x + 100y = 75(605)\r\n" );
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document.write( "Multiply 75 times 605 get 45375\r\n" );
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document.write( "             x + y = 605\r\n" );
document.write( "        45x + 100y = 45275\r\n" );
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document.write( "Solve the first equation for x\r\n" );
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document.write( "                 x = 605 - y\r\n" );
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document.write( "Substitute that for x in the second equation\r\n" );
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document.write( "        45x + 100y = 45275\r\n" );
document.write( "45(605 - y) + 100y = 45275\r\n" );
document.write( "27225 - 45y + 100y = 45275\r\n" );
document.write( "       27226 + 55y = 45275\r\n" );
document.write( "               55y = 18150\r\n" );
document.write( "                 y = 18150/55\r\n" );
document.write( "                 y = 330 ml of pure alcohol\r\n" );
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document.write( "Substitute in\r\n" );
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document.write( "                 x = 605 - y\r\n" );
document.write( "                 x = 605 - 330\r\n" );
document.write( "                 x = 275 ml of mixture\r\n" );
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document.write( "Now do the same with your numbers.\r\n" );
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document.write( "Edwin

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