Book Excerpts : Close Encounters with the Brainteaser Job Interview

The good news is hiring is going up. The bad news is the competition is really fierce. Here's how to get a leg up.

BY JOHN KADOR

Move over "So, tell me about yourself" or "What is your biggest weakness?" Make way for "Why are manhole covers round?" or "How would you test a salt shaker?"

Companies from Wall Street to Silicon Valley are discarding traditional softball interview questions in favor of brain crunching teasers, riddles and logic puzzles. With so many qualified candidates competing for each position, interviewers are desperate to identify those who demonstrate enthusiasm for taking on new challenges, an appetite for solving difficult problems and a certain amount of creative audacity. They are using tough and tricky questions to see if applicants rise and shine to the challenge of surviving in today's hypercompetitive work environment or slink off into the sunset.

Microsoft and other high tech firms popularized the practice, but now prospective employees never know when a taxing brainteaser may pop up. "What an applicant knows gets him or her through the first interview," says Ed Milano, an interviewer who routinely peppers candidate interviews with brainteasers. By the time the applicant gets to Milano, vice president of marketing and program development at Design Continuum, a product design consulting firm with offices in Boston, Milan and Seoul, the candidate's aptitude or experience are no longer in question.

For Milano to extend a job offer, he has to see how the applicant thinks under stressful conditions, the environment that often describes life at a consultancy that assists clients with make-or-break strategic design programs. "We never solve the same problem twice; every engagement is unique," Milano says. "So we're looking for people who think about new things in a new way, eager to move past established limits and are confident enough to push their teammates over their respective boundaries."

That's a tall order for any job interview, but Milano, like many recruiters, has often found that starting with a brainteaser is effective. Logic puzzles and riddles have a long tradition in fast-moving high-tech companies where being quick on your feet is an asset. As the rest of the world has embraced the attributes of the start-up mentality of the high-tech computer company, many recruiters are adopting the in-your-face style of interviewing associated with technology-heavy industries. Some recruiters believe that brainteasers are valid tools to gauge the creativity, intelligence, passion, resourcefulness, etc., of applicants. Others are willing to accept that puzzles are little more than interview stunts that may or may not reveal aspects of the applicant's character, but there are worse ways to assess a candidate's intellectual capacities than essentially asking him or her to think out loud.

What kinds of puzzles and brainteasers are in recruiters' tool chests these days? The questions, and the desired responses, fall into four general categories.

Puzzles That Have Correct Answers

These types of questions simply test an applicant's sense of the physical world, aptitude in using logic and the ability to communicate effectively.

Puzzle 1: There's a fishbowl with 200 fish and 99 percent are guppies. How many guppies do you need to remove to get to the point where 98 percent of the remaining fish are guppies?
Desired response: 100 guppies. But just as important, the interviewer wants to hear how you got to the answer. So do your thinking out loud and don't leave out any steps, even if they are obvious. There are many approaches to solving the problem. Here's one:

Let's see . . . I'm only going to be removing guppies. So if I remove any other kind of fish, I'm going to put it back. That means the population of non-guppies remains the same. Okay, 99 percent of 200 fish means there are 198 guppies and 2 non-guppies. Now, how many guppies do I need to remove so that 2 non-guppies represent 2 percent (100-98)? The answer is 98. So I need to end up with 98 guppies from 198. That means I must remove 100 guppies.

Puzzle 2: You are in a room with three light switches, each of which controls one of three light bulbs in the next room. Your task is to determine which switch controls which bulb. All lights are initially off, and you can't see into one room from the other. You may inspect the room only once. How can you determine which switch is connected to which light bulb?
Desired Response: Call the switches 1, 2 and 3. Leave Switch 1 off. Turn Switch 2 on for five minutes and then turn it off. Turn Switch 3 on. Enter the room. If a bulb is on, it's controlled by Switch 3. Feel the light bulbs for heat. The warm bulb is controlled by Switch 2. The bulb that is off and cold is controlled by Switch 1.

Puzzle 3: An Arab sheikh tells his two sons to race their camels to a distant city to see who will inherit his fortune. The one whose camel comes in second will receive all the inheritance. Since neither brother wants to come in first, they wander the desert aimlessly for days. Finally they come across a wise man and ask for his advice. After hearing the advice, both brothers jump on the camels and race as fast as they can to the city. What does the wise man say?
Desired response: The key is to listen carefully to the question. The most elegant answer is "Exchange camels with your brother." Now the brother who enters the city first wins the inheritance because his original camel will come in second.

Puzzle 4: You are in a stopped car with a helium balloon floating in the passenger compartment. All the windows are closed. The car accelerates forward. With respect to the passenger compartment, does the balloon move forward, move backward, or stay stationary?
Desired Response: The balloon will move forward in the passenger compartment because inertia forces the air molecules back, creating low pressure up front into which the balloon moves. Try it.


Puzzles That Don't have Correct Answers

While these puzzles don't have correct answers (or, more precisely, no one really cares what the correct answers are), they definitely have incorrect answers. These questions, often used by consulting firms such as McKinsey and Boston Consulting Group, frequently call on the applicant to apply gross order of estimation skills.

Puzzle 5: How many gas stations are there in America? How many piano tuners are there in Canada?
Desired Response: The interviewer doesn't know or care about the answer. The interviewer wants to see how the applicant reframes the question, breaks it down and communicates a rational solution. Design Continuum's Milano recalls a candidate who took on the gas station question: "Let's see," she began. "On my way here I passed four gas stations . . ." At this point, Milano was satisfied. The applicant had started a clear process of extrapolating from the specific to the general.

Puzzle 6: Which way should the key turn in a car door to lock it? Clockwise or counterclockwise?
Desired Response: Most interviewers say it really doesn't matter as long as candidates defend their decision. But there is a preferred answer for right-handed people: The design of the human hand and wrist make clockwise turns easier for right-handed people. The opposite is true for left-handed people.

Puzzle 7: How would you weigh a Boeing 747 without using scales?
Desired Response: There are many solutions, but one elegant response is that you put the jet on a large boat and paint a mark on the hull where the water line is. Now remove the jet and the boat rises. Then, load the ship with items of known weight until it sinks to the line you painted. The total weight of the items will equal the weight of the jet.

Puzzle 8: If you had to eliminate one of the 50 U.S. states, which one would you select. Be prepared to give specific reasons why you chose the state you did.
Desired Response: No right answer, unless you're applying for a job with Microsoft, in which case Washington State is definitely a non-starter. The best course is to reframe the question in some compelling way. Another idea: don't start with the name of a state, but walk the interviewer through your logic and see where you end up together. Humor always helps. There are dozens of creative answers. Here are two of them.

1. Well, I don't want to be responsible for eliminating actual people. So I'd eliminate the political entity of a state by ceding it to Canada, perhaps a state that shares a border with Canada, such as North Dakota or Vermont. Would I still be able to visit?

2. I'd eliminate Wyoming [you get points for knowing that Wyoming is the least populous state], but only if the people and natural attributes can be relocated to a theme park on the Las Vegas strip.

Deconstruction Puzzles

While the first two classes of puzzles test a candidate's deductive reasoning — going from the specific to the general — deconstruction puzzles test inductive skills — going from the general to the specific. The main point? Can the candidate see how the Big Picture flows from many details.

Puzzle 9: Here's a PDA (or cell phone or digital camera). Deconstruct it for me.
Desired Response: What the interviewer is watching for is the ability to conceptually articulate the functional elements of a device. Many approaches are possible. Some candidates talk about the physical components: the keyboard is for data entry; the LCD is for data display, etc. Milano recalls one candidate who took his PDA, turned it on and for five minutes silently analyzed the data it contained. Then the applicant put the PDA down and said, "This is the tool you use to manage the intersection of your personal and work lives." And then he went through all the functions — calendar, contacts, e-mail, notes — and how they helped Milano manage and preserve the boundaries.

Performance Puzzles

The fourth type of puzzle calls for the candidate to actually perform a task that calls on logic and problem-solving skills.

Puzzle 10: Please take this and sell it to me. Tell me about its design excellence, features, benefits and values.
Desired Response: The recruiter gives the candidate a device or product — a pen, a coffee mug, it hardly matters. This task tests not only an applicant's raw promotional ability, particularly useful if the position involves sales, but his or her ability to reconceptualize — the imagination required to repurpose a device or technology to new uses. Recruiters expect applicants to ask questions. But not too many questions. "I tolerate one or two questions, but then I say, 'You'd better start selling me,'" Milano says.

Puzzle 11: Design a spice rack for a blind person.
Desired Response: This not a trivial problem and the solution, whatever it turns out to be, is less important than the applicant's ability to define, perhaps redefine, the problem and its constraints. For starters, many recruiters want to hear something like, "Okay, the goal here is to design an integrated spice storage and dispensing system that is friendly for blind people to use, is that right?" To many recruiters, it's a plus for the applicant to check out if her understanding of the problem is correct. Some recruiters want the candidate to suggest some contact with blind people instead of assuming he knows what the issues for blind people are. Others give applicants extra credit if they can get beyond the conventional form factor of a spice rack and propose an innovative package. After that, recruiters want to hear the applicant consider the components of the problem (jars, lids, labeling, organizing system) and how each interrelates to the needs of the target consumer. Most candidates specify labels in Braille. After that the answers can take a variety of directions. The issue is can the applicant articulate a solution, and what happens when the recruiter challenges the design? Does the applicant immediately agree with the recruiter or does he defend his conception.

Puzzle 12: Here's a saltshaker. Show me how you would you test it.
Desired Response: The operative word is "show." The recruiter is not looking for profound originality here, but is looking for more than words. This is a variety of the deconstruction puzzle with a call to action. Does the applicant understand the functions of a salt shaker and how it is used? If so, the evaluation will be broken down into logical steps. For example, does the saltshaker really contain salt? Some saltshakers — especially those in fourth-grade cafeterias — contain sugar. The applicant now tastes the contents. Is the top on securely, a design flaw common in high school lunchrooms? Test the top. Are the holes sufficient for dispensing the right amount of salt? Do the test.

Strategies for Solutions

Not comfortable with these types of questions? That's the point. They are meant to be unnerving.
But some common sense tips can make it easier.

Many job applicants outsmart themselves by being too clever. Puzzles offered in job interviews are almost always about process more than answers. The trick is to find the trick. Here are 10 tips to guide you:

Ultimately, blame it on Microsoft. Ever since Microsoft popularized this stressful approach to interviewing (its perennial puzzler: why are manhole coves round?), more and more companies are looking for that certain approach that will uncover the perfect mind for the job.