Which statement about fuel/air ratios is correct?

The statement regarding the fuel/air ratios is accurate because the mixture ratio for best power indeed requires a richer mixture compared to that for maximum economy.

In aircraft engines, the mixture ratio is crucial for performance and efficiency. The best power mixture is typically richer than the maximum economy mixture because richer mixtures provide more fuel relative to air, allowing for a greater energy release during combustion. This is essential during operations where maximum thrust is required, such as takeoffs or climbs.

On the other hand, the maximum economy mixture aims to minimize fuel consumption, optimizing the fuel/air ratio for the best efficiency rather than maximum power output. This leaner mixture helps with fuel efficiency during cruise conditions but sacrifices some power potential compared to the richer mixture.

Understanding this distinction is key for pilots and mechanics when setting mixtures for different phases of flight, ensuring optimal performance and fuel management.