document.write( "Question 1196702: Mike wants to make 10 ml of a 69% sugar solution by mixing together a 25% sugar solution and a 80% sugar solution. How much of each solution must he use? \n" ); document.write( "
Algebra.Com's Answer #829654 by greenestamps(13200)\"\" \"About 
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\n" ); document.write( "The response from the other tutor shows the setup for solving the problem by the standard method for \"mixture\" problems. Of course you want to use a method something like that if a formal algebraic solution is required.

\n" ); document.write( "But in problems like this where the numbers are \"nice\" -- as they are in this problem -- a quick and easy solution can be obtained by seeing where the percentage of the mixture lies between the percentages of the two ingredients.

\n" ); document.write( "Look at the three percentages (on a number line, if it helps) and observe/calculate that 69 is 44/55 = 4/5 of the way from 25 to 80. That means 4/5 of the mixture needs to be the 80% ingredient.

\n" ); document.write( "Since the mixture is to be 10 ml, that means using 8 ml of the 80% sugar solution and 2 ml of the 25% sugar solution.

\n" ); document.write( "ANSWER: 8 ml of the 80% solution; 2 ml of the 25% solution

\n" ); document.write( "CHECK:
\n" ); document.write( ".80(8)+.25(2) = 6.4+.5 = 6.9
\n" ); document.write( ".69(10) = 6.9

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\n" ); document.write( "Postscript....

\n" ); document.write( "If this method of solving the problem looks like magic, observe that the formal solution from the other tutor arrives at that same fraction 44/55 for the fraction of the mixture that must be the 80% sugar solution....

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