document.write( "Question 276407: How many kgs of salt must be added to 24 kg of 20% salt solution in order to increase the concentration of salt to 40%? \n" ); document.write( "

Algebra.Com's Answer #854143 by ikleyn(53742) $\"\"$ $\"About$

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\n" ); document.write( "How many kgs of salt must be added to 24 kg of 20% salt solution in order to increase
\n" ); document.write( "the concentration of salt to 40%?
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\n" ); document.write( "\n" ); document.write( "        When the problems are talking about salt solutions of high concentration, it is useful to remember\r
\n" ); document.write( "\n" ); document.write( "        that water solutions of NaCl can not have concentration higher than 27%.\r
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\n" ); document.write( "\n" ); document.write( "        At 27%, the solution becomes saturated, and concentration can not go higher than this value.\r
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\n" ); document.write( "\n" ); document.write( "        This is a standard fact, which students learn from the Science course in their 6-th grade. \r
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\n" ); document.write( "\n" ); document.write( "        The second reason why I write these lines, is that the calculations in the post by @mananth \r
\n" ); document.write( "\n" ); document.write( "        are incorrect and inaccurate and lead to wrong answer.\r
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\n" ); document.write( "\n" ); document.write( "        I came to bring a correct solution.\r
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document.write( "The balance equation for this problem is\r\n" );
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document.write( "    x + 0.2*24 = 0.4*(x+24),\r\n" );
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document.write( "where 'x' is the salt mass to add.\r\n" );
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document.write( "Simplify and find 'x'\r\n" );
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document.write( "    x + 4.8 = 0.4x + 9.6,\r\n" );
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document.write( "    x - 0.4x = 9.6 - 4.8,\r\n" );
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document.write( "      0.6x   =     4.8\r\n" );
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document.write( "         x   =     4.8/0.6 = 8.\r\n" );
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document.write( "ANSWER.  8 kilograms of salt should be added.\r\n" );
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\n" ); document.write( "\n" ); document.write( "Solved correctly and explained about the saturation limit.\r
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