1. **State the problem:** We need to find the slope of the line on the graph that shows the cost of transporting sugar versus the weight of sugar in tons. 2. **Recall the formula for slope:** The slope $m$ of a line passing through two points $(x_1, y_1)$ and $(x_2, y_2)$ is given by $$m = \frac{y_2 - y_1}{x_2 - x_1}$$ 3. **Identify points from the graph:** From the description, two points on the line are approximately $(1, 1600)$ and $(5, 4000)$. 4. **Calculate the slope:** $$m = \frac{4000 - 1600}{5 - 1} = \frac{2400}{4}$$ 5. **Simplify the fraction:** $$m = \frac{\cancel{2400}}{\cancel{4}} = 600$$ 6. **Interpret the slope:** The slope $600$ means the cost increases by 600 dollars for each additional ton of sugar transported. 7. **Answer the questions:** (a) The slope of the line is $600$. (b) The cost increases by $600$ for each ton of sugar transported. Note: The user mentioned $400$ in the question, but based on the graph points given, the slope is $600$.