document.write( "Question 314779: 1. Sam invested some money at 7% and then invested $4,000 more than twice this amount at 9%. His total annual income from the two investments was $2,860. How much was invested at 9%?\r
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\n" ); document.write( "\n" ); document.write( "2. How many liters of a 10% alcohol soultion must be mixed with 30 liters of a 40% solution to get a 20% solution? \n" ); document.write( "
Algebra.Com's Answer #225122 by stanbon(75887)\"\" \"About 
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Sam invested some money at 7% and then invested $4,000 more than twice this amount at 9%. His total annual income from the two investments was $2,860. How much was invested at 9%?
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\n" ); document.write( "0.07x + 0.09(2x+4000) = 2850
\n" ); document.write( "Multiply thru by 100 to get:
\n" ); document.write( "7x + 18x + 36000 = 285000
\n" ); document.write( "25x = 249000
\n" ); document.write( "x = $9960 (amt invested at 7%)
\n" ); document.write( "2x+4000 = 2*9960+4000 = $23,920 (amt. invested at 9%
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\n" ); document.write( "\n" ); document.write( "2. How many liters of a 10% alcohol solution must be mixed with 30 liters of a 40% solution to get a 20% solution?
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\n" ); document.write( "alcohol + alcohol = alcohol
\n" ); document.write( "0.10x + 0.40*30 = 0.20(x+30)
\n" ); document.write( "Multiply thru by 100 to get:
\n" ); document.write( "10x + 40*30 = 20x + 20*30
\n" ); document.write( "10x = 20*30
\n" ); document.write( "x = 60 liters (amt. of 10% solution needed for the mixture)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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