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> how many ping pong balls fit in a 747 This one does seem useful. Being able to do back-of-the-napkin (i.e. fermi problem) calculations is a pretty good skill

> how many ping pong balls fit in a 747 This one does seem useful. Being able to do back-of-the-napkin (i.e. fermi problem) calculations is a pretty good skill.

watwut 6y ago
Back of napkin that requires you to know what 747 is wrong be correlated with anything programming related.
crocal 6y ago
Actually a typical GMAT question...
toast0 6y ago
It might be an OK problem if the interviewee is familiar with 747s and ping pong balls, and will be interacting with physical objects as part of their job. I have a terrible time with physical measurments and area and space, but thankfully it's not relevant to my work.
CydeWeys 6y ago
Google does still use questions like this, it's just that they're relevant to programming/system design. So a question might be "How many servers are needed to run Gmail?" The reason the 747 question is bad is because it has little to do with programming and a lot to do with how much you happen to know about planes and ping pong balls and how to estimate volumes of irregularly shaped objects, none of which have much if any correlation with programming ability.
- joshuamorton 6y ago
  They don't (for SWEs), or at least you aren't supposed to. I think for PMs there may be questions more in this realm, but for SWEs, your questions should all be programming problems.
  - CydeWeys 6y ago
    A System Design interview is required for all senior+ SWE candidates, plus other roles like at least SRE: https://www.youtube.com/watch?v=Gg318hR5JY0 https://www.youtube.com/watch?v=Gg318hR5JY0 Similar but smaller questions along these lines are given to more junior candidates often enough too, as one of multiple questions.
    - joshuamorton 6y ago
      Your right though that candidates can get system design interviews, but "how many servers does it take to run gmail" is not anything like a system design interview. "How would you architect gmail" is. System design questions by their nature don't really have a correct answer. Your right though that candidates can get system design interviews.
      - CydeWeys 6y ago
        Estimating how much traffic needs to be handled and what kind of resources it would take to handle it are absolutely part of both of those questions, which in reality are the same interview problem because a System Design interview isn't a single question but rather a long series of guided questions that cover architecture, scaling, and a lot more.

> how many ping pong balls fit in a 747 This one does seem useful. Being able to do back-of-the-napkin (i.e. fermi problem) calculations is a pretty good skill.

watwut 6y ago

Back of napkin that requires you to know what 747 is wrong be correlated with anything programming related.

crocal 6y ago

Actually a typical GMAT question...

toast0 6y ago

It might be an OK problem if the interviewee is familiar with 747s and ping pong balls, and will be interacting with physical objects as part of their job. I have a terrible time with physical measurments and area and space, but thankfully it's not relevant to my work.

CydeWeys 6y ago

Google does still use questions like this, it's just that they're relevant to programming/system design. So a question might be "How many servers are needed to run Gmail?" The reason the 747 question is bad is because it has little to do with programming and a lot to do with how much you happen to know about planes and ping pong balls and how to estimate volumes of irregularly shaped objects, none of which have much if any correlation with programming ability.

joshuamorton 6y ago
They don't (for SWEs), or at least you aren't supposed to. I think for PMs there may be questions more in this realm, but for SWEs, your questions should all be programming problems.
- CydeWeys 6y ago
  A System Design interview is required for all senior+ SWE candidates, plus other roles like at least SRE: https://www.youtube.com/watch?v=Gg318hR5JY0 https://www.youtube.com/watch?v=Gg318hR5JY0 Similar but smaller questions along these lines are given to more junior candidates often enough too, as one of multiple questions.
  - joshuamorton 6y ago
    Your right though that candidates can get system design interviews, but "how many servers does it take to run gmail" is not anything like a system design interview. "How would you architect gmail" is. System design questions by their nature don't really have a correct answer. Your right though that candidates can get system design interviews.
    - CydeWeys 6y ago
      Estimating how much traffic needs to be handled and what kind of resources it would take to handle it are absolutely part of both of those questions, which in reality are the same interview problem because a System Design interview isn't a single question but rather a long series of guided questions that cover architecture, scaling, and a lot more.