document.write( "Question 509905: A chemist work on a new project needs 12liters of 50% acid solution, The stockroom only has 40% and 70% solutions. how much of each solution should be mixed together to form 12 liters of a 50% solution. \n" ); document.write( "
Algebra.Com's Answer #341651 by Maths68(1474)\"\" \"About 
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Solution A
\n" ); document.write( "Concentration = 40%=0.4
\n" ); document.write( "Amount = x
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\n" ); document.write( "Solution B
\n" ); document.write( "Concentration = 70%=0.7
\n" ); document.write( "Amount = 12-x
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\n" ); document.write( "Resultant Solution
\n" ); document.write( "Concentration = 50%=0.5
\n" ); document.write( "Amount = 12 liters
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\n" ); document.write( "(Concentration of A * Amount of A)+(Concentration of B * Amount of B)=(Concentration of Resultant * Amount of Resultant)
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\n" ); document.write( "0.4x+0.7(12-x)=0.5*12
\n" ); document.write( "0.4x+8.4-0.7x=6
\n" ); document.write( "-0.3x=6-8.4
\n" ); document.write( "-0.3x=-2.4
\n" ); document.write( "Divide by -0.3 both sides
\n" ); document.write( "-0.3x/-0.3=-2.4/-0.3
\n" ); document.write( "x=8
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\n" ); document.write( "Amount of solution A = x = 8 liters
\n" ); document.write( "Amount of solution B = 12-x = 12-8 = 4 liters\r
\n" ); document.write( "\n" ); document.write( "Conclusion
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\n" ); document.write( "chemist needs to mix 8 liters of 40% and 4 liters of 70% solutions to get 12 liters of a 50% solution.\r
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