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You can put this solution on YOUR website!
\n" ); document.write( "Tutor @ikleyn has shown a solution using the usual algebraic method; she has also pointed you towards several other examples of similar problems which use the same method.
\n" ); document.write( "It is of course useful to know that method. However, there is a much faster and easier way to find the answer to ANY mixture problem like this where two \"ingredients\" are being mixed.
\n" ); document.write( "For your problem, here is the entire set of calculations required:
\n" ); document.write( "(1) 50-30 = 20; 30-20 = 10
\n" ); document.write( "(2) 20:10 = 2:1
\n" ); document.write( "(3) 2 parts 30% acid to 1 part 50% acid
\n" ); document.write( "(4) 2/3 of 120 ounces = 80 ounces of 30% acid; 1/3 of 120 ounces = 40 ounces of 50% acid
\n" ); document.write( "It's even faster if you think in terms of what those calculations mean. Here is the way I think of it:
\n" ); document.write( "\"The 30% target is twice as close to 20% as it is to 50% (step (1) above); therefore the solution must use twice as much of the 20% ingredient as the 50% ingredient (step (2) above). A 2:1 ratio with a total of 120 ounces means 80 ounces of 20% and 40 ounces of 50% (steps 3 and 4 above).\" \n" ); document.write( "