document.write( "Question 978494: A chemist has liquid fertilizer solutions that are 20% and 60% nitrogen. How many gallons of each of these solutions should the chemist mix to obtain 250 gallons of solution that is 30% nitrogen? \n" ); document.write( "
Algebra.Com's Answer #599894 by richwmiller(17219)\"\" \"About 
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\n" ); document.write( "We know the total amount is 250 gallons
\n" ); document.write( "We know the percentage of the total amount is 30%
\n" ); document.write( "We know the total amount has 75 gallons of 100%
\n" ); document.write( "We want to know the amount of solution at 20%
\n" ); document.write( "We want to know the amount of solution at 60%
\n" ); document.write( "x+y=250,
\n" ); document.write( "0.2*x+0.6*y=0.3*250
\n" ); document.write( "0.2*x+0.6*y=75
\n" ); document.write( "x=250-y
\n" ); document.write( "0.2*(250-y)+0.6*y=75
\n" ); document.write( "50-0.2y+0.6*y=75
\n" ); document.write( "0.4*y=25
\n" ); document.write( "We now know amount of solution at 60%
\n" ); document.write( "y=62.5 gallons at 60%
\n" ); document.write( "x=250-y
\n" ); document.write( "We now know amount of solution at 20%
\n" ); document.write( "x=187.5 gallons at 20%
\n" ); document.write( "check
\n" ); document.write( "0.2*187.5+0.6*62.5=0.3*250
\n" ); document.write( "37.5+37.5=75
\n" ); document.write( "75.0=75
\n" ); document.write( "ok
\n" ); document.write( " \n" ); document.write( "
\n" );