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#24. Quick brainteaser games for consulting/ tech job interviews

Try to quickly ESTIMATE 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, first, iden­tify a logical approach that can help “guessti­mate” an appropriate range–say + or – 30% of the actual answer– and then com­plete the cal­cu­la­tions (ide­ally men­tally, but you can also take notes) to pro­vide a good-enough 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?.


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; 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.


Next brain teaser in SharpBrains’ top 25 series:

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8 Responses

  1. Tim says:


    1) 10,000 times (1 ton versus 100 grams)

    2) 800 firefighters (80 stations x 10 in each)

    3) 5,000 trees

  2. tiki says:

    1. 8000

    2. 650

    3. 1500

  3. Alvaro says:

    Again, the key here is to try, plan the steps towards the solution, and do the mental calculations.That’s the brain exercise.


    1. Around 150,000. Elephant: 4,000 kg on average; mouse is 25 grams.

    2. Around 350 firefighters on duty on any given day, out of a pool of 1700 firefighting and emergency medical field personnel

    3. “There are over 26,000 trees of approximately 175 species in the Park.” More information at

  4. Mitch says:

    I said 80000 times as heavier (elephant 2000kg, mouse 25g).

    Im australian so i have no idea about those american-based questions.

  5. Aaron says:

    1. 14,000 times heavier

    2. 1,300

    3. 3,624

  6. Bushy Mouse says:

    1 million

  7. datasam says:

    my no-calc guesstimations were:

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