How many ping-pong balls would fit in the Mediterrean Sea? Can you swim faster in water or syrup? When there’s a wind blowing, does a round-trip by plane take more time, less time, or the same time? Today, a number of companies have taken a page out of the Google playbook and have begun asking interviewees brainteasers, logic puzzles and mind-bending riddles. The question you probably have right now is, Why?
Tech companies have long asked prospective employees to answer off-the-wall questions in an effort to identify the most nimble-minded applicants. But since the Great Recession, many non-tech companies are now asking would-be employees to estimate the number of bottles of shampoo produced in the world every year, or how many integers between 1 and 1,000 contain a 3.
TIME Moneyland talked to William Poundstone, author of the new book, Are You Smart Enough to Work at Google?, about these unconventional interviewing methods, how Google revolutionized the interview, and how he would weigh his head.
When did this method of interviewing prospective employees begin?
Oxford and Cambridge, which for at least 100 years have had very difficult admission interviews. They give you curveball question like, “Does a Girl Scout have a political agenda?” But I think IBM was the first big company to do this. This was just after World War II, when computers were very new and they realized that programming a computer is not electrical engineering. They were getting people from all sorts of fields, so they started throwing in logic puzzles as a way to see if people were capable of thinking in new ways. These types of questions have been part of the culture of tech companies for quite some time. But the incredibly tough job market has done a lot to spread this to more mainstream companies.
What type of companies do this now?
I’m now finding that more people are reporting them from non-technology companies. It’s very big in banking and consulting, but even in retail, where you would never have had questions like that in the past.
So these questions are even popping at employers like Walmart?
Yeah, which is kind of overkill, I think. But companies are almost desperate in this job market because they’ll get 20 applicants, all of whom would’ve been great if the economy had been better. But they have to find some rationale for saying, This is why we’re going to hire this person and not these 19 other people.
The most famous example of this seems to be the Google billboards. Can you explain those?
Back in 2004, Google had these billboards where they would ask for the first 10-digit prime number found in the consecutive digits of e, and you were supposed to go to a certain website, if you were smart enough to figure that out. You could then send them an e-mail and your resume.
How are these questions better than the information gathered from a more traditional job interview?
There’s so much evidence that traditional interviews really don’t tell you very much. But research has shown that work sampling works: The best way to predict how someone is going to do on the job is to pose questions that are similar to the sorts of things they’d be doing. One of the reasons that Google’s interviews are so notorious is that there’s so much work in the interview. If you’re a coder, you might spend 80% of your interview doing actual coding problems. But they also throw in these offbeat questions. One of the things they hope to address in the interviews is, Are you open to new ideas? Can you think in flexible ways?
As the job market improves, do you think these types of interview questions will continue?
I think when it does get a little more normal, places like Walmart will stop asking really difficult questions.
I was surprised that your book is really meant to prepare anyone looking for a job, even outside the tech sector.
The book is designed for people who want to get a little confidence with these kinds of questions. Just reading them over, going through the explanations I give, tends to build people’s confidence.
So how can people prepare for these interviews?
These questions are difficult questions, which means that the first approach that pops into your head is probably going to be wrong. So a good approach is just to say, Well, I think the obvious approach would be this, but that’s probably not going to work, and then give your analysis of why the obvious approach fails. That gets you talking. You want to avoid dead air. And usually once you analyze how one thing’s wrong, that’s a good first step towards just brainstorming various other strategies. They like to see people who are very free with ideas, even if they’re half-baked.
Do you have a favorite brainteaser?
One that I like is: How would you weigh your head? Because there’s no really good answer to that. Smart people usually think of the Archimedes’ Principle. Archimedes had to weigh this crown for some king to find out if it was solid gold, and he stepped in the bath in ancient Syracuse and realized that the water level went up and he thought, A-ha! Eureka! He could dunk the crown in water to find it’s volume. You can kind of do that here. You could fill a basin of water to the brim and if you dunk your head in that water and collect the water that spills over, the volume of that water is going to be exactly the same as the volume of your head, which is helpful. But they’re not asking for the volume, they’re asking for the weight of your head. And you can say that the density of the human body is pretty close to that of water, just from the fact that we barely float in the swimming pool. It’s an approximation and it’s not necessarily a great answer, but maybe someday someone will come up with a definitive answer.
In a lot of these, it seems as if it’s not about the answer. It’s about working your way to an answer.
It’s about the thought process. Because with a lot of these, where you have to estimate something crazy, like how many ping-pong balls could fit in the Mediterranean Sea basin if it was drained, the interviewer doesn’t know the answer.
How frustrating. So I’m assuming that you’re qualified to work at Google now?
Probably not in terms of having the actual skills to work there, but I’m pretty good with some of these offbeat questions.
You could ace the interview, at least.
[laughs] Yeah, I suppose so.