Final answer:
For medium concrete jobs, a cement mixer is the most efficient and suitable tool to use, as it ensures a consistent mix and is practical for larger volumes.
Step-by-step explanation:
To mix concrete for medium jobs, you should use a cement mixer. This equipment is designed for efficiently mixing large volumes of concrete. For smaller tasks, a shovel and a wheelbarrow might suffice for mixing and transporting concrete, respectively.
However, for medium-scale projects, a cement mixer ensures a consistent mix and it is more practical than manual methods. Though a trowel is used in masonry for specific tasks such as leveling, spreading, and shaping concrete, it is not the right tool for mixing.