Lets say we have a 1000 sf of wall
Worker 1 completes 100 sf per day.

So if he worked on it, the duration is:
1000/100 = 10 days
And the work is: duration x assigned units = 10 days x 8 hours x 1 worker = 80 worker hours


Now lets say we also have a worker 2. And he produces 200 sf of wall per day. If he worked on it, the duration will be 1000/200 = 5 days.

And work would be 5 days x 8 hours x 2 worker = 80 worker hours. Is this correct? In other words, here I must say two worker, as if two of worker 1 is working on it, because worker 2 is worth two of worker 1, and this way the total work amount doesn't change right? Because the total work amount MUST be the same for both cases, since the task is the same, which is the 1000 sf of wall, right?