1. The problem asks to find $D(15)$, which means we need to find the distance Lamar can drive when there are 15 liters of gas in the tank. 2. From the graph description, the function $D(x)$ is linear, starting at $(0,0)$ and reaching approximately $(19,350)$. 3. Since the function is linear, we can find the slope $m$ using the points $(0,0)$ and $(19,350)$: $$m = \frac{350 - 0}{19 - 0} = \frac{350}{19}$$ 4. The linear function can be written as: $$D(x) = mx + b$$ Since it passes through the origin, $b=0$, so: $$D(x) = \frac{350}{19} x$$ 5. To find $D(15)$, substitute $x=15$: $$D(15) = \frac{350}{19} \times 15 = \frac{350 \times 15}{19} = \frac{5250}{19}$$ 6. Simplify the fraction: $$\frac{5250}{19} \approx 276.32$$ 7. Interpretation: Lamar can drive approximately 276.32 kilometers when he has 15 liters of gas in the tank. Final answers: (a) $D(15) = 276.32$ (b) Lamar can drive about 276.32 kilometers when he has 15 liters of gas in the tank.