document.write( "Question 838678: I have a 300ml solution of 14% bleach but need to make it into 10% how much water do I add? \n" ); document.write( "

Algebra.Com's Answer #715867 by ikleyn(52781) $\"\"$ $\"About$

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document.write( "Let W be the volume of water (in mL) to add to your original solution.\r\n" );
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document.write( "When you add, your final solution will have the volume of (300+W) mL. \r\n" );
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document.write( "This volume will contain the same 0.14*300 mL of bleach as the original solution.\r\n" );
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document.write( "So, the concentration of the final solution will be this ratio   of the \"pure bleach\" to the total liquid volume.\r\n" );
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document.write( "According to the condition, this ratio must be equal to 10%, or 0.1.\r\n" );
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document.write( "It gives you an equation\r\n" );
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document.write( " = 0.1.\r\n" );
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document.write( "It is your major/basic equation for the given problem.\r\n" );
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document.write( "As soon as you got this equation, the setup part is done and completed.\r\n" );
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document.write( "This equation is often called a \"concentration\" equation, since its both sides describe the concentration of the final solution.\r\n" );
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document.write( "To solve the equation, multiply both sides by (300+W). You will get\r\n" );
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document.write( "0.14*300 = 0.1*(300 + W),\r\n" );
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document.write( "0.14*300 = 0.1*300 + 0.1*W,\r\n" );
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document.write( "0.14*300 - 0.1*300 = 0.1*W  ====>  0.04*300 = 0.1*W  ====>  W =  = 0.4*300 = 120.\r\n" );
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document.write( "Answer.  You need to add 120 mL of water.\r\n" );
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document.write( "Check.    = 0.1 = 10%.   ! Correct !\r\n" );
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