One of the most frustrating things about hiring someone new is that it can take forever to get them trained and up to speed. When a candidate asks a question like this, he lets the interviewers know that he will find a way to help as soon as possible, which is a major bonus. This again gives you the opportunity to sell yourself as someone who can help on those projects, and as an added bonus-it lets you know what skills you need to brush up on before your next interview or even before starting the job.