The way I understand this, is that we will have 3 (liters of water) +0.5 (half a liter of lemonade) =3.5 liters of liquid
so the question would be: how many times does \(\frac{1}{3}\) fit into 3.5?
I count this like this:
\(\frac{3.5}{ \frac{1}{3} } = \frac{3.5*3}{1} =9+1.5=10.5\)
if you want to divide by a fraction, you need to multiply by the reverse of it.
so the answer is: 10 servings of lemonade ( and a little bit will be left over for half a serving).