document.write( "Question 830613: A 18 gallon salt-water solution contains 15% pure salt. how much pure salt should be added to produce the solution to 20% salt? \n" ); document.write( "
Algebra.Com's Answer #500977 by josgarithmetic(39618)\"\" \"About 
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Best judgement about this is that an estimate is possible, assuming 18 gallons of water as \"pounds\" of water and that 15% of this value is the amount of salt dissolved in it.\r
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\n" ); document.write( "\n" ); document.write( "You must use the density of water, 8.345 pounds per gallon; or whatever value you can best accept.\r
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\n" ); document.write( "\n" ); document.write( "\"18%2Agallons%288.345%2Apound%2Fgallon%29=2703.78\" pounds\r
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\n" ); document.write( "\n" ); document.write( "Next, assuming that concentration is MASS per MASS, we can continue...\r
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\n" ); document.write( "\n" ); document.write( "\"%28%280.15%29%282704%29%2B1.00%2Am%29%2F%282704%2Bm%29=0.20\", using m for the mass of salt to add, in \"pounds\".
\n" ); document.write( "Solve for m.
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