Breanne made pineapple drinks by mixing pineapple syrup and water in the ratio 2:7. If she used 4 L of pineapple syrup, how much water did she use?

1. The ratio of pineapple syrup to water is 2:7. This means for every 2 parts of syrup, there are 7 parts of water.
2. Breanne used 4 L of pineapple syrup. Set up the proportion:

\frac{2}{7} = \frac{4}{x}

where \( x \) is the amount of water used.

3. Cross-multiply to solve for \( x \):

2x = 7 \cdot 4

4. Simplify:

2x = 28

5. Solve for \( x \):

x = \frac{28}{2}

6. Calculate:

x = 14

7. Therefore, Breanne used 14 L of water.

Answer: 14 \text{ L}