Answer:
Step-by-step explanation:
You currently have 2 ways of doing this problem. Here is a 3rd way.
This method is referred to as "alligation" in pharmacy and other preparations. You arrange what you HAVE (100% and 30%) and what you W ANT (40%) in a grid and subtract cross-wise to obtain what you NEED, as shown below:
HAVE.......WANT.....NEED
100%.....................20...
...............40%..............
30%......................40....
So, you need to use 20 PARTs of the 100% and 50 PARTS of the 30%. Since parts is actually quarts in this problem, and the 50 parts is actually told to you to be 3 quarts, then the 20 parts is 1.2 quarts. This later calculation would be
40parts/20parts = 3quarts/x quarts and x = 1.2 quarts
