As a product manager, I believe that Google could potentially be successful in the ride-sharing business. Google has a strong brand reputation and extensive resources that could allow it to enter the market with a competitive edge. In terms of how many cars Google would need for a mid-sized city, it would depend on several factors such as population density, demand, and competition. To determine the appropriate number of cars, Google would need to conduct market research and gather data on user behavior and preferences. In addition, Google could consider implementing a fleet management system that optimizes the allocation and utilization of vehicles. This could help reduce costs and improve efficiency, allowing Google to scale its operations as needed. Overall, while there are certainly challenges and risks associated with entering the ride-sharing market, I believe that Google has the potential to succeed if it approaches the business with a strategic and data-driven mindset.