First of all, from the distance, the distance from Zhengzhou to Xi 'an is about 500 kilometers, which takes about 6 hours. For a medium-sized car, the fuel consumption is about 8 liters per 100 km, so it takes about 80 liters of fuel for a single trip. According to the oil price per liter of 6 yuan, the cost of one-way fuel is about 480 yuan, plus the toll of expressway is about 200 yuan, and other small expenses such as parking fees are about 300 yuan. Therefore, the total round-trip cost is about 780 yuan.
Secondly, from the perspective of time and efficiency, driving requires a lot of time and energy, and may face traffic congestion and other problems. In contrast, the train ticket price from Zhengzhou to Xi 'an is only 239 yuan. Taking the high-speed train can save time and energy, and avoid driving fatigue and traffic congestion.
Based on the above factors, it is not cost-effective to drive from Zhengzhou to Xi 'an. Although driving may be more flexible and free, considering the high cost and time investment, it may be more wise to choose other modes of transportation, such as train or high-speed rail.