ANSWER
10 cups
EXPLANATION
3 jugs of water is added to make 2 cups of lemon to make Egyptian lemonade.
This means we can write the ratio of jugs of water to cups of lemon as:
3 : 2
15 jugs of water are to be used. Let the cups of lemonade be x.
we have that the ratio is:
15 : x
Since both ratios must be equal, we have:
3 : 2 = 15 : x
We can rewrite that as:
[tex]\begin{gathered} \frac{3}{2}\text{ = }\frac{15}{x} \\ \text{Cross}-mu\text{ltiply:} \\ 3\cdot\text{ x = 15 }\cdot\text{ 2} \\ 3x\text{ = 30} \\ \text{Divide through by 3:} \\ x\text{ = }\frac{30}{3} \\ \text{x = 10 cups} \end{gathered}[/tex]10 cups of lemon are needed.