Alternative and related questions:
How many projects can you handle at one time?
The meaning behind the question:
If the interviewer is asking this question, you can be reasonably sure that handling multiple projects at the same time is going to be a feature of your new job. The interviewer wants to see if you are going to be able to cope with this – and how. They'll be looking for sound evidence of your abilities in this respect.
Your answer:
You might think this question is very similar to the previous one – but it's not. Simultaneously juggling numerous different projects is definitely not the same as multitasking.
There's only one correct answer to this question and it's a resounding 'Yes'! Go on to back up your 'Yes' with some evidence, preferably an example. The interviewer is unlikely to be asking you this question unless you have previous experience of project management so you should be able to drawn on a decent example from your career history. An unqualified 'Yes' is a worthless answer. It has to be supported by some proof.
Example:
Yes. I've had plenty of experience handling a very full workload and dealing with numerous different projects simultaneously. When starting out in my current job, I came in to a situation where they were behind schedule on a number of projects and yet also had several new projects which needed to be started. I certainly had my hands very full indeed; it was quite a juggling act! I persuaded the management to allocate sufficient resources so we could complete the overdue projects without suffering further financial penalties and I simultaneously got us going on the new range of projects as quickly as possible so as to not disappoint the clients. It was very hard going but I soon got things under control and, once the backlog had been cleared and we were up-to-date, we were able to consistently adhere to timescales and deadlines in the future.