One such trend was injecting “oddball questions” into the interview, such as: “How many Ping-Pong balls can you fit in a jet airliner?” Of course no interviewer in their right mind expected you to come up with a definitive answer. The idea behind those oddball questions was something like this:
In every job, there will be oddball situations coming at you every once in a while. How do you deal with that: Do you get defensive (“What the &*$# does that have to do with anything??”) or do you acknowledge, even welcome the oddball question as an opportunity to show your capacity for outlining the path to a solvable problem: “First of all, are we taking the seats out? Are we filling the kerosene tanks as well? (…)”
You get the idea. And while those typical oddball questions have been on the wane, the underlying premise remains: Every so often, we all are faced with something we don’t know, and have to find out about. In the above example of the Ping-Pong balls, it is quite obvious you wouldn’t really have to know that. But what if the interview question does have bearing on the job you are interviewing for, such as: “How would you go about in developing this niche market in our new sales territory?”
I wouldn’t have a definitive answer to that one. For starters, I would need more information—read up on the demographics of that new territory, consult with existing area sales directors and field sales reps about what has been working thus far, etc. I would relate all that in my answer to that question, so the interviewer would know I was capable of defining and framing the problem, and resourceful enough to formulate steps to tackle the challenge.
Another way of looking at it: If any interview candidate were able to hand the interviewer a definitive answer on a silver platter, then the interviewer might respond (or at least think): “Great! Now we can do it ourselves!”
Really, it is okay not to know something (as long as it’s not like you don’t know anything—duh!). When you don’t know something, what matters is you show the interviewer how excited you are to put your nose to the grindstone. Maybe you can inject a story about how you have handled a similar learning curve before.