document.write( "Question 1442: How many gallons of a 70% acid solution must be mixed with 30 gallons of a 16% solution to obtain a solution that is 60% acid? \n" ); document.write( "
Algebra.Com's Answer #475 by AnlytcPhil(1806) $\"\"$ $\"About$
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How many gallons of a 70% acid solution must be mixed 
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document.write( "with 30 gallons of a 16% solution to obtain a solution that is 
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document.write( "60% acid?
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document.write( "We are mixing a stronger 70% acid solution with a weaker 16% 
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document.write( "acid solution to obtain a medium strength 60% acid solution. 
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document.write( "Let x = the number of gallons of the stronger
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document.write( "We mix the following:
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document.write( " x gallons of stronger
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document.write( "30 gallons of weaker
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document.write( "and therefore we get
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document.write( "x+30 gallons of medium strength solution
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document.write( "Now we figure the number of gallons of pure alcohol contained 
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document.write( "in all three of these:
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document.write( "The x gallons of stronger solutions contains 0.70x gallons of pure 
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document.write( "alcohol (and the rest is water, which we ignore.)
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document.write( "The 30 gallons of weaker solution contains 0.16(30) or 4.8 gallons 
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document.write( "of pure alcohol (and the rest is water, which we ignore).
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document.write( "The x+30 gallons of the final medium-strength solution contains 0.60(x+30) gallons of pure alsohol (and the rest is water, which we ignore).   
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document.write( "Now 
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document.write( "   The number of gallons of pure alcohol in the stronger +
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document.write( "       The number of gallons of pure alcohol in the weaker solution =
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document.write( "           The number of gallons of pure alcohol in the medium-strength
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document.write( "           solution.  
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document.write( "or  0.70x + 4.8 = 0.60(x+30)
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document.write( "Can you solve that? Answer: x = 132 gallons. 
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document.write( "Check:
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document.write( "The 132 gallons of 70% contains 92.4 gallons of pure alcohol and
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document.write( "39.6 gallons of water.
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document.write( "The 30 gallons of 16% contains 4.8 gallons of pure alcohol and 
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document.write( "25.2 gallons of water.
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document.write( "When they are mixed:
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document.write( "The 162 gallons of 60% contains 97.2 gallons of pure alcohol and 
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document.write( "64.8 gallons of water.
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document.write( "Adding up the liquid: 132 gallons + 30 gallons = 162 gallons
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document.write( "Adding up the pure acid: 92.4 gallons + 4.8 gallons = 97.2 gallons 
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document.write( "Adding up the water: 39.6 gallons + 25.2 gallons = 64.8 gallons
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document.write( "It all adds up!
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document.write( "Edwin 
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