Problem Solving (PS) | Re: A 30% alcohol mixture is added to a 50% alcohol mixture to form a 10

The method thatArchit3110 used has a bunch of different names, but it's one of the best strategies out there for weighted averages! A really good way to use it is to visualize the concentrations of our original mixtures (30% and 50%) and the concentration of our final mixture (45%) on a number line:

<--30%---------------45%-----50%-->

Notice how the resulting concentration is much closer to 50% — this indicates that there is more of the 50% alcohol mixture than of the 30% alcohol mixture