Be honest and tell them how you would find out the answer.
So an interviewer asks you a question and you have no idea what the answer is, but they’re asking you for a reason so you should talk with them to figure out what the reason is.
So you should do a few things
1) Clarify that you understand what they’re asking
2) Talk through your options and
3) Give a potential solution and
4) Bring the conversation back to your strengths.
So it might look like this:
Interviewer: “How do you tie up a cat with string?”
You: [in your mind] “I have no idea!?
You: [Clarifying] “I’m not sure because I’ve never had to do that in my last job, I assume that the need to tie up a cat with string comes up often at your organization?”
Interviewer: “Not every day, but on a weekly basis-one of the programmers cats impregnated one of the engineers’ cats. And we can’t just no longer allow people to bring their cats to work!
You: [Chuckling along with them to show that you understand their problem, even if you don’t.]
Interviewer: “But there are a lot of kittens around and they have ruined a lot of our prototypes by chewing on them. I guess that’s what we get for trying to make a cell phone powered by catnip…”
You: [Clarifying] So let me understand, you have a problem-which doesn’t occur on a daily basis that involves a lot of cats-some of which are still quite young kittens?
Interviewer: “No, they’ve aged, so they’re all adults-and they’ve all been fixed after Janice from accounting got involved.”
You: [Clarifying] Why do they need to be tied in string? Have you tried other methods of keeping them away from the prototypes? What other information can you tell me about this problem?
Interviewer: “String seems like the best solution to us. We tried putting them all in a closet, and they ate through our CTO’s messenger bag, so that’s out. Plus it took too long to get them all into one room.”
You: [Talking Through Options] “I think I have enough information about the problem, but I’m afraid that because I’ve never attempted to tie up any animal, let alone a cat, I am unable to give you the answer you need.
What I would do if I were faced with this at your organization is to first, do some research-maybe call a veterinarian or someone who works at animal rescue for their expertise. Then I would use whatever strategy they feel is best. Have you done a web search for this problem?”
Interviewer: “Oh yeah, we’ve got a Pinterest board full of pictures of cats with string, but they all seem stylized, like they’re just adorable pictures? It hasn’t led to any solution.”
You: [Bringing it Back to Yourself] “I do have a PhD in CS, have manged my own Mime rental business and I have over 10 years of experience in Email Marketing. But I haven’t faced this exact problem. From what we’ve spoken about do you think that if I were given time and followed the steps I outlined, I would be able to solve this problem? I really am interested in this job and I don’t want this one omission to be held against me. I would love to do some research and email you after this interview because I really am interested in this problem.”
Obviously this example is fictional, but it gives you an idea of how to make sure that you’re showing that you’re invested and that you would work forward on a problem. Some interviewers like to ask questions to put people on the spot-how you react can make all of the difference.