document.write( "Question 736924: How many liters of 400L of 20% NaCl solution must be replaced with 70% NaCl solution so that the resulting solution is 41%? \n" ); document.write( "

Algebra.Com's Answer #450054 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+a+\"$ = liters of 20% solution to be removed
\n" ); document.write( "Also, $\"+a+\"$ = liters of 70% solution to be added
\n" ); document.write( " $\".2a+\"$ = liters of NaCl removed
\n" ); document.write( " $\"+.7a+\"$ = liters of NaCl added
\n" ); document.write( "--------------
\n" ); document.write( " $\"+.7a+-+.2a+=+.5a+\"$ liters of NaCl are added
\n" ); document.write( " $\"+.2%2A400+=+80+\"$ liters of NaCl to start with
\n" ); document.write( "--------------
\n" ); document.write( " $\"+%28+80+%2B+.5a+%29+%2F+400+=+.41+\"$
\n" ); document.write( " $\"+80+%2B+.5a+=+.41%2A400+\"$
\n" ); document.write( " $\"+.5a+=+164+-+80+\"$
\n" ); document.write( " $\"+.5a+=+84+\"$
\n" ); document.write( " $\"+a+=+168+\"$
\n" ); document.write( "168 liters of 400L of 20% NaCl solution must be
\n" ); document.write( "replaced with 70% NaCl solution
\n" ); document.write( "check:
\n" ); document.write( " $\"+%28+80+%2B+.5a+%29+%2F+400+=+.41+\"$
\n" ); document.write( " $\"+%28+80+%2B+.5%2A168+%29+%2F+400+=+.41+\"$
\n" ); document.write( " $\"++80+%2B+84+=+.41%2A400+\"$
\n" ); document.write( " $\"+164+=+164+\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );