document.write( "Question 786696: a chemist has 2 solutions of HNO3. one has 40% concentrated and the other has 23% concentration. how many liters of each solution must be mixed to obtain 121 liters of a 29% solution? \n" ); document.write( "
Algebra.Com's Answer #477946 by DrBeeee(684)\"\" \"About 
You can put this solution on YOUR website!
I get some funny numbers, but I think I'm right.
\n" ); document.write( "Let x = number of liters at a 40% concentrate.
\n" ); document.write( "Let y = number of liters at a 23% concentrate.
\n" ); document.write( "Then we have
\n" ); document.write( "(1) x + y = 121
\n" ); document.write( "and
\n" ); document.write( "(2) 0.40x + 0.23y = 0.29*121
\n" ); document.write( "Multiply both sides of (2) by 100 to get
\n" ); document.write( "(3) 40*x + 23*y = 29*121
\n" ); document.write( "Solve (1) for x and put into (3) to get
\n" ); document.write( "(4) 40*(121 - y) + 23*y = 29*121 or
\n" ); document.write( "(5) 40*121 - 40*y + 23*y = 29*121 or
\n" ); document.write( "(6) -17*y = (29 - 40)*121 or
\n" ); document.write( "(7) y = 11*121/17
\n" ); document.write( "Then from (1) we get
\n" ); document.write( "(8) x = 121 - 11*121/17 or
\n" ); document.write( "(9) x = 6*121/17
\n" ); document.write( "Let's check this with (2).
\n" ); document.write( "Is (0.40*6*121/17 + 0.23*11*121/17 = 0.29*121)?
\n" ); document.write( "Is (2.4*121/17 + 2.53*121/17 = 0.29*121)?
\n" ); document.write( "Is (4.93*121/17 = 0.29*121)?
\n" ); document.write( "Is (0.29*121 = 0.29*121)? Yes
\n" ); document.write( "Answer: Use about 42.7 liters of the 40% concentrate and about 78.3 liters of the 23% concentrate of HNO3 to get 121 liters at a 29% concentration.\r
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