document.write( "Question 363416: An amount of 40% acid solution is to be mixed wih enough 10% acid solution to make 25% acid solution. If there are to be 2o liters of the final mixture, how much of each solution should be mixed together? \n" ); document.write( "
Algebra.Com's Answer #259118 by josmiceli(19441)\"\" \"About 
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Let \"a\" = liters of 40% solution needed
\n" ); document.write( "Let \"b\" = liters of 10% solution needed
\n" ); document.write( "given:
\n" ); document.write( "\".4a\" = liters of alcohol in 40% solution
\n" ); document.write( "\".1b\" = liters of alcohol in 10% solution
\n" ); document.write( "\".25%2A2+=+.5\" = liters of alcohol in final solution
\n" ); document.write( "--------------------
\n" ); document.write( "(1) \"%28.4a+%2B+.1b%29%2F2+=+.25\"
\n" ); document.write( "(2) \"a+%2B+b+=+2\"
\n" ); document.write( "from (1)
\n" ); document.write( "(1) \".4a+%2B+.1b+=+.5\"
\n" ); document.write( "(1) \"4a+%2B+b+=+5\"
\n" ); document.write( "Subtract (2) from (1)
\n" ); document.write( " \"4a+%2B+b+=+5\"
\n" ); document.write( "\"-a+-+b+=+-2\"
\n" ); document.write( "\"3a+=+3\"
\n" ); document.write( "\"a+=+1\"
\n" ); document.write( "and
\n" ); document.write( "\"a+%2B+b+=+2\"
\n" ); document.write( "\"1+%2B+b+=2\"
\n" ); document.write( "\"b+=+1\"
\n" ); document.write( "1 liter of 40% solution and 1 liter of 10% solution are needed
\n" ); document.write( "check:
\n" ); document.write( "(1) \"%28.4a+%2B+.1b%29%2F2+=+.25\"
\n" ); document.write( "(1) \"%28.4%2A1+%2B+.1%2A1%29%2F2+=+.25\"
\n" ); document.write( "\".5%2F2+=+.25\"
\n" ); document.write( "\".5+=+.5\"
\n" ); document.write( "OK
\n" ); document.write( "
\n" );