How do I create a table that requires calculations with different variables?

There are a few pitfalls along the way.
The Solve block solves for two variables, but Prime does not allow vectors that contain function definitions.
You could do it like this:

This function with both values as the result could now be broken down again into two individual functions. Since the Solve block sometimes does not find a solution (for values of Q less than 0.809993 m³/s), this error can be intercepted using try..onerror:

Now you could use the functions for plotting,

but of course you can also use them to create a table of values

EDIT: Just noticed that in the picture I forgot to add the unit for Q in the header text. Is fixed in the attached file.

Prime 10 file attached