document.write( "Question 172456: To make 10 kg of aluminum alloy with 60% aluminum, a scientist wants to use two metals with 45% and 70% aluminum content respectively. How much of each metal should she use? (Hint: The amount of aluminum in the alloy is the sum of the amounts in the original meatls.) \n" ); document.write( "

Algebra.Com's Answer #127353 by Mathtut(3670) $\"\"$ $\"About$

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lets call the amount of metal for the 45% and 70%, a and b respectively
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\n" ); document.write( "a+b=10............eq 1
\n" ); document.write( ".45a+.7b=.6(10)...eq 2
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\n" ); document.write( "rewrite eq 1 to b=10-a and plug b's value into eq 2
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\n" ); document.write( ".45a+.7(10-a)=6
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\n" ); document.write( ".45a+7-.7a=6
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\n" ); document.write( ".25a=1
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\n" ); document.write( " $\"highlight%28a=4%29\"$ kg
\n" ); document.write( " $\"highlight%28b=10-4=6%29\"$ kg \n" ); document.write( "

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