document.write( "Question 601799: you need to use 3 solutions of drug H containing respectively 50%, 20%, and 5% to make 600ml of 10% drug H. How much of the 50% will you use?\r
\n" ); document.write( "\n" ); document.write( "Who try to solve it for me. \n" ); document.write( "
Algebra.Com's Answer #380026 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
Let \"+a+\" = ml of 50% solution needed
\n" ); document.write( "Let \"+b+\" = ml of 20% solution needed
\n" ); document.write( "Let \"+c+\" = ml of 5% solution needed
\n" ); document.write( "given:
\n" ); document.write( "(1) \"+a+%2B+b+%2B+c+=+600+\" ml
\n" ); document.write( "(2) \"+%28+.5a+%2B+.2b+%2B+.05c+%29+%2F+600+=+.1+\"
\n" ); document.write( "This is only 2 equations and 3 unknowns,
\n" ); document.write( "but I can guess at a solution
\n" ); document.write( "--------------------------------
\n" ); document.write( "(2) \"+.5a+%2B+.2b+%2B+.05c+=+60+\"
\n" ); document.write( "(2) \"+50a+%2B+20b+%2B+5c+=+6000+\"
\n" ); document.write( "Multiply both sides of (1) by \"+5+\" and
\n" ); document.write( "subtract (1) from (2)
\n" ); document.write( "(2) \"+50a+%2B+20b+%2B+5c+=+6000+\"
\n" ); document.write( "(1) \"+-5a+-+5b+-+5c+=+3000+\"
\n" ); document.write( "\"+45a+%2B+15b+=+3000+\"
\n" ); document.write( "\"+3a+%2B+b+=+200+\"
\n" ); document.write( "I'll guess that \"+a+=+50+\" and \"+b+=+50+\"
\n" ); document.write( "then
\n" ); document.write( "(2) \"+50a+%2B+20b+%2B+5c+=+6000+\"
\n" ); document.write( "(2) \"+50%2A50+%2B+20%2A50+%2B+5c+=+6000+\"
\n" ); document.write( "(2) \"+2500+%2B+1000+%2B+5c+=+6000+\"
\n" ); document.write( "(2) \"+3500+%2B+5c+=+6000+\"
\n" ); document.write( "(2) \"+5c+=+2500+\"
\n" ); document.write( "(2) \"+c+=+500+\"
\n" ); document.write( "That works, so I can use
\n" ); document.write( "50 ml of 50% solution needed
\n" ); document.write( "50 ml of 20% solution needed
\n" ); document.write( "500 ml of 5% solution needed
\n" ); document.write( "There can be other solutions, but this works\r
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