document.write( "Question 267345: please solve\r
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\n" ); document.write( "\n" ); document.write( "a solution containing 30% juice is mixed with a solution containing 10% juice to make 100 gallons of solution that makes 12% juice.How much of the 30% solution was used?
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Algebra.Com's Answer #196230 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
In words:
\n" ); document.write( "(gallons of juice in 1st solution + gallons of juice in 2nd solution / (gallons of final solution) = 12%
\n" ); document.write( "Let \"a\" = gallons of 30% solution needed
\n" ); document.write( "Let \"b\" = gallons of 10% solution needed
\n" ); document.write( "given:
\n" ); document.write( "(1) \"a+%2B+b+=+100\"
\n" ); document.write( "------------------
\n" ); document.write( "\"%28.3a+%2B+.1b%29%2F100+=+.12\"
\n" ); document.write( "\".3a+%2B+.1b+=+12\"
\n" ); document.write( "(2) \"3a+%2B+b+=+120\"
\n" ); document.write( "Now subtract (1) from (2)
\n" ); document.write( "(2) \"3a+%2B+b+=+120\"
\n" ); document.write( "(1) \"-a+-+b+=+-100\"
\n" ); document.write( "\"2a+=+20\"
\n" ); document.write( "\"a+=+10\"
\n" ); document.write( "and, since
\n" ); document.write( "\"a+%2B+b+=+100\"
\n" ); document.write( "\"b+=+100+-+10\"
\n" ); document.write( "\"b+=+90\"
\n" ); document.write( "10 gallons of the 30% solution were needed
\n" ); document.write( "check:
\n" ); document.write( "\"%28.3a+%2B+.1b%29%2F100+=+.12\"
\n" ); document.write( "\"%28.3%2A10+%2B+.1%2A90%29%2F100+=+.12\"
\n" ); document.write( "\"%283+%2B+9%29%2F100+=+.12\"
\n" ); document.write( "\"12%2F100+=+.12\"
\n" ); document.write( "\".12+=+.12\"
\n" ); document.write( "OK
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