document.write( "Question 122501: an alloy of tin is 15% tin weighs 20 pounds. a second alloy is 10% tin. how much of the second alloy must be added to the first alloy to get a 12% mixture.
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\n" ); document.write( "the amount would be ( ) pounds \n" ); document.write( "

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an alloy of tin is 15% tin weighs 20 pounds. a second alloy is 10% tin. how much of the second alloy must be added to the first alloy to get a 12% mixture.
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\n" ); document.write( "Let x = no. of pounds of 10% alloy that must be added
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\n" ); document.write( "The resulting 12% mixture would weigh (x+20) lbs
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\n" ); document.write( "A typical mixture equation
\n" ); document.write( ".15(20) + .10x = .12(x+20)
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\n" ); document.write( " 3 + .1x = .12x + 2.4
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\n" ); document.write( ".1x - .12x = 2.4 - 3
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\n" ); document.write( "-.02x = - .6
\n" ); document.write( "x = $\"%28-.6%29%2F%28-.02%29\"$
\n" ); document.write( "x = +30 lbs of 10 % tin required
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\n" ); document.write( "Check solution, we know the final amt will weigh 20+30 = 50
\n" ); document.write( ".15(20) + .10(30) = .12(50)
\n" ); document.write( " 3 + 3 = 6; confirms out solution \n" ); document.write( "

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