1. The problem states the ratio of red cars to black cars is 79 : 51. 2. We want to express this ratio in the form $n : 1$, where $n$ is a decimal number. 3. To do this, divide both parts of the ratio by the number of black cars, which is 51. 4. Calculate $n = \frac{79}{51}$. 5. Performing the division: $$n = \frac{79}{51} \approx 1.5490$$ 6. Round $n$ to 2 decimal places: $1.55$. 7. Therefore, the ratio in the form $n : 1$ is $1.55 : 1$. This means for every 1 black car, there are approximately 1.55 red cars.