To make a paint mixture, you need 2 liters of water for every 3 liters of paint. How many liters of water are needed for 15 liters of paint?

Solution:

1. Given:
- Ratio of water to paint: 2:3
- Amount of paint: 15 liters

2. Set up the proportion for water:
Let x be the liters of water needed.
\frac{2}{3} = \frac{x}{15}

3. Solve for x:
2 \cdot 15 = 3 \cdot x
30 = 3x
x = \frac{30}{3}
x = 10

Answer:
\text{10 liters of water are needed for 15 liters of paint.}