document.write( "Question 16261: How much water should be added to 30 gallons of a solution that is 70% antifreeze in order to get a mixture that is 60% antifreeze? \n" ); document.write( "

Algebra.Com's Answer #7917 by Earlsdon(6294) $\"\"$ $\"About$

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Here's one approach: the 30 gallons of 70% antifreeze solution is 30% water and you want to make a solution that is 60% antifreeze and 40% water. So you will add x gallons of water to the 30% water solution.
\n" ); document.write( "Change the percents to their decimal equivalents. \r
\n" ); document.write( "\n" ); document.write( " $\"30%280.3%29+%2B+x+=+%2830+%2B+x%29%280.4%29\"$ Simplify and solve for x, the number of gallons of water to be added.
\n" ); document.write( " $\"9+%2B+x+=+12+%2B+0.4x\"$ Subtract 0.4x from both sides.
\n" ); document.write( " $\"9+%2B+0.6x+=+12\"$ Subtract 9 from both sides.
\n" ); document.write( " $\"0.6x+=+3\"$ Finally, divide both sides by 0.6
\n" ); document.write( " $\"x+=+5\"$ \r
\n" ); document.write( "\n" ); document.write( "You will need to add 5 gallons of water to the 30 gallons of 70% antifreeze solution to make 35 gallons of 60% antifreeze solution.\r
\n" ); document.write( "\n" ); document.write( "Check:\r
\n" ); document.write( "\n" ); document.write( " $\"30%280.3%29%2B+5+=+35%280.4%29\"$
\n" ); document.write( " $\"9+%2B+5+=+14\"$
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