document.write( "Question 506102: How many liters each of a 35% acid solution and a 60% acid solution must be used to produce 70 liters of a 45% acid solution? (Round to two decimal places if necessary.)\r
\n" ); document.write( "\n" ); document.write( "Let x=amount of a 35% solution
\n" ); document.write( "let y=amount of a 60% solution\r
\n" ); document.write( "\n" ); document.write( "Which gives me x+y=70 and 0.35x+0.60y=31.5
\n" ); document.write( "What I don't understand is how they got 31.5 in the second equation.
\n" ); document.write( "Please help. \n" ); document.write( "

Algebra.Com's Answer #340086 by solver91311(24713) $\"\"$ $\"About$

You can put this solution on YOUR website!
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\n" ); document.write( "\n" ); document.write( "The amount of pure acid in the 35% solution is 0.35 times

, the amount of pure acid in the 60% solution is 0.60 times

, and the amount of pure acid in the final 45% solution is 0.45 times 70 since the total amount at the end is 70 liters. And

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\n" ); document.write( "\n" ); document.write( "By the way, I wouldn't introduce the second variable at all. You can save yourself a step by saying that

represents the amount of 35% solution and then, since the total amount of solution is 70 liters, the amount of 60% solution has to be

. That way my single equation for this problem comes out to:\r
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\n" ); document.write( "\n" ); document.write( "John
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\n" ); document.write( "My calculator said it, I believe it, that settles it
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$\"The$

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