How many hours a week do you work?
Be careful before you answer the question about how many hours a week you work. You do not want to be perceived as a slacker; otherwise, you are not also impressed as someone who works too much. In some companies, the working hours are normally 40 hours per week and everyone went home on time. In other places, all people can work for 50 or 60 hours a week.
However, working longer may not necessarily give a better result – it may mean that you are not productive enough to do the job done in a reasonable amount of time.
Therefore, unless you are confident about the company’s culture and expectations, the safest answer is not to mention the exact amount of hours. Instead, you can mention that you work as much as necessary to get the job done.