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Top 7 Brainteasers for Job Interviews and Brain Challenge

A recent CNN arti­cle explains well why a grow­ing num­ber of com­pa­nies use brain­teasers and log­ic puz­zles of a type called “guessti­ma­tions” dur­ing job inter­views:

- “Seem­ing­ly ran­dom ques­tions like these have become com­mon­place in Sil­i­con Val­ley and oth­er tech out­posts, where com­pa­nies aren’t as inter­est­ed in the cor­rect answer to a tough ques­tion as they are in how a prospec­tive employ­ee might try to solve it. Since busi­ness­es today have to be able to react quick­ly to shift­ing mar­ket dynam­ics, they want more than engi­neers with high IQs and good col­lege tran­scripts. They want peo­ple who can think on their feet.”

What are tech­nol­o­gy com­pa­nies (Google, Microsoft, Ama­zon) and con­sult­ing com­pa­nies (McK­in­sey, Boston Con­sult­ing Group, Accen­ture…) look­ing for? They want employ­ees withbrain teasers job interview good so-called Exec­u­tive Func­tions: prob­lem-solv­ing, cog­ni­tive flex­i­bil­i­ty, plan­ning, work­ing mem­o­ry, deci­sion-mak­ing, even emo­tion­al self-reg­u­la­tion (don’t try to solve one of these puz­zles while being angry, or stressed out).

Want to try a few? Below you have our Top 7 Guesstimations/ Log­ic Puz­zles for Brain Chal­lenge:

Please try to GUESS the answers to the ques­tions below based on your own log­i­cal approach. The goal is not to find out (or Google) the right answer, but to 1) iden­ti­fy the log­ic approach that will help “guessti­mate” an appro­pri­ate range, say + or – 30% of the actu­al answer, and then 2) com­plete the cal­cu­la­tions (ide­al­ly men­tal­ly, but you can also take notes) to pro­vide an esti­mate.

Ready. Set. Go!

1) How many times heav­ier than a mouse is an ele­phant?.

2) How many fire­fight­ers are there in San Fran­cis­co?.

3) How many trees are there in NYC’s Cen­tral Park?.

4) How many shoes have you had in your life?.

5) How many golf balls can fit in a school bus?.

6) In 1999, how were these baby boy names ranked by pop­u­lar­i­ty: Kevin, Jose, Hugh.

7) What is the weight of a large com­mer­cial air­plane?.

The Answer appear below. Again, the key here is to try, plan the steps towards the solu­tion, and do the men­tal cal­cu­la­tions to find a rea­son­able range. That’s the brain chal­lenge. The goal is not to find the pre­cise cor­rect answer.


1) Around 150,000. An aver­age ele­phant weighs 4,000 kg on aver­age; an aver­age mouse 25 grams.

2) Around 350 fire­fight­ers on duty on any giv­en day, out of a pool of 1700 fire­fight­ing over­all staff.

3) There are over 26,000 trees (of approx­i­mate­ly 175 species) in the Park.

4) We don’t know (or need to know) how many pairs you have had.

5)  About 500,000, assum­ing the bus is 50 balls high, 50 balls wide, and 200 balls long.
6) Rank­ings of baby boy names in 1999, accord­ing to Social Secu­ri­ty Admin­is­tra­tion: 1. Jose (#30), 2. Kevin (#32), 3. Hugh (#830).

7) For a Boe­ing 747:
— Emp­ty: around 400,000 pounds (lbs), or 181 met­ric tons
— Max­i­mum Take­off Weight: around 825,000 pounds, or 374 met­ric tons
— For con­text, the weight of an emp­ty Hum­mer is 8,600 pounds.

More Con­text on Exec­u­tive Func­tions:
If you want to learn more about what they are, here are some quotes from my Inter­view with neu­ropsy­chol­o­gist Dr. Elkhonon Gold­berg:

Alvaro Fer­nan­dez: Please tell us more about what the Frontal Lobes are.

Elkhonon Gold­berg: We researchers typ­i­cal­ly call them the Exec­u­tive Brain. The pre­frontal cor­tex is young by evo­lu­tion­ary terms, and is the brain area crit­i­cal to adapt to new sit­u­a­tions, plan for the future, and self-reg­u­late our actions in order to achieve long-term objec­tives. We could say that that part of the brain, right behind our fore­head, acts as the con­duc­tor of an orches­tra, direct­ing and inte­grat­ing the work of oth­er parts of the brain.

I pro­vide a good exam­ple in The Exec­u­tive Brain book, where I explain how I was able to orga­nize my escape from Rus­sia into the US. Sig­nif­i­cant­ly, the path­ways that con­nect the frontal lobes with the rest of the brain are slow to mature, reach­ing full oper­a­tional state between ages 18 and 30, or maybe even lat­er. And, giv­en that they are not as hard-wired as oth­er parts of the brain, they are typ­i­cal­ly the first areas to decline.

Ready for that job inter­view now– on either end of the table?


More brain teas­er games:

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As seen in The New York Times, The Wall Street Journal, BBC News, CNN, Reuters,  SharpBrains is an independent market research firm tracking how brain science can improve our health and our lives.

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