document.write( "Question 153167: A doctor wants to use three lots of ichthammol containing 50%, 20% and 5% ichthammol respectively. In what proportion should they be mixed to prepare a 10% ichthammol ointment? \n" ); document.write( "
Algebra.Com's Answer #112751 by ankor@dixie-net.com(22740)\"\" \"About 
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A doctor wants to use three lots of ichthammol containing 50%, 20% and 5% ichthammol respectively. In what proportion should they be mixed to prepare a 10% ichthammol ointment?
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\n" ); document.write( "With 3 different mixtures, I don't think there is a unique solution
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\n" ); document.write( "Assume a convenient resulting amt like 60
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\n" ); document.write( "Let x = amt of 50% stuff, and the amt of 20% of stuff
\n" ); document.write( "then
\n" ); document.write( "(60-2x) = amt of 5% stuff
\n" ); document.write( ":
\n" ); document.write( ".50x + .20x + .05(60-2x) = .10(60)
\n" ); document.write( ".7x + 3 - .10x = 6
\n" ); document.write( ".7x - .1x = 6 - 3
\n" ); document.write( ".6x = 3
\n" ); document.write( "x = \"3%2F.6\"
\n" ); document.write( "x = 5 units of 50% and 20% stuff
\n" ); document.write( "then
\n" ); document.write( "60 - 2(5) = 50 units of 5% stuff
\n" ); document.write( ":
\n" ); document.write( "We have 5:5:50
\n" ); document.write( "or
\n" ); document.write( "1:1:10 is the ratio of the 3 mixtures to obtain the 10% result
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\n" ); document.write( "Check:
\n" ); document.write( ".5(1) + .2(1) + .05(10) = .1(12)
\n" ); document.write( ".5 + .2 + .5 = 1.2 \n" ); document.write( "
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