Question 1095079
<br>one answer that is not an answer but rather a reference to a place where you can see her method of solving the problem; and another answer without any clue to you about how to get that answer....<br>
You can follow the path the first responder gave you, to try a solution by the traditional algebraic method.  But give this shortcut method a try and see if you understand it; if you do, you will be able to solve mixture problems like this with much less work.<br>
You are mixing ingredients with butterfat percentages of 3% and 15% to get a mixture of 6% butterfat.  Look at how far the 6% is from each of the 15% and 3%:<br>
15-6 = 9
6-3 = 3<br>
The 6% is "3 times as close" to 3% as it is to 15% (because 9 is 3 times as much as 3).  That means you need 3 times as much of the 3% milk as you need of the 15% cream.<br>
3 times as much milk as cream and a total of 20 L means 15 L of the 3% milk and 5 L of the 15% cream.