The table shows the distances and times that four rowboats traveled. Which rowboat was the fastest?

To determine which rowboat was the fastest, we need to calculate the speed of each rowboat. Speed can be calculated using the formula:

\[
\text{Speed} = \frac{\text{Distance}}{\text{Time}}
\]

We will calculate the speed for each rowboat:

1. **Rowboat A:**
- Distance = 160 meters
- Time = 40 seconds
\[
\text{Speed} = \frac{160 \text{ meters}}{40 \text{ seconds}} = 4 \text{ m/s}
\]

2. **Rowboat B:**
- Distance = 150 meters
- Time = 50 seconds
\[
\text{Speed} = \frac{150 \text{ meters}}{50 \text{ seconds}} = 3 \text{ m/s}
\]

3. **Rowboat C:**
- Distance = 180 meters
- Time = 30 seconds
\[
\text{Speed} = \frac{180 \text{ meters}}{30 \text{ seconds}} = 6 \text{ m/s}
\]

4. **Rowboat D:**
- Distance = 100 meters
- Time = 20 seconds
\[
\text{Speed} = \frac{100 \text{ meters}}{20 \text{ seconds}} = 5 \text{ m/s}
\]

Now, we can compare the speeds:

- Rowboat A: 4 m/s
- Rowboat B: 3 m/s
- Rowboat C: 6 m/s
- Rowboat D: 5 m/s

**Conclusion:**
Rowboat C was the fastest with a speed of 6 m/s.