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If Richard Feynman applied for a job at Microsoft (2002)

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Re: If Richard Feynman applied for a job at Microsoft (2002)

#161

Post by RHSeeger »

s0rce wrote: post #119
Hokusai wrote: post #86

Earlier quoted context omitted.

The problem is that it is impossible to give a good answer without context. Did it matter a 2% error? There are cost limits? Maybe you don't even need to know the number of ping pong balls but it would be faster to transport them by ship....

Isn't the context an interview, ie. give a decent order of magnitude estimate with back of the envelope methods.

Probably, but to be fair, when a client asks "can you put a button here that sends an alert email when it's clicked?"... a reasonable first question may very well be "what is it you're hoping to accomplish here... so we can tell if such a button is really the right answer". In many cases, the button isn't the right answer. And being the kind of person that digs to find out what the problem trying to be solved actually is... can be very important.

Re: If Richard Feynman applied for a job at Microsoft (2002)

#162

Post by hogFeast »

conjecTech wrote: post #143
okareaman wrote: post #75

How many ping pong balls would it take to fill a 747? Why do you ask? What problem are you trying to solve? We want to understand your thought process I'd think it was stupid to fill a 747 with ping pong balls and think about something else

I don't get the derision for these kinds of problems. And I think it's unlikely Feynman would have found this unhelpful. These are commonly referred to as Fermi problems. Fermi was a physicist of Feynman's generation - they were probably standing together at Trinity when Fermi did the famous yield approximation. The other physicists held this ability in such esteem they gave it a name and remembered him for it. The q…

That would be true if everyone wasn't also asking the same questions. So you are just testing whether the person knows that you ask that question or has interviewed at other places that do (I have seen this in other industries too: firm adopts some "interview technique", no women get through, no under-represented groups get through, they are baffled but put it down to their process being a completely objective identifier of innate genius...kind of ignoring that some of these places are hiring tens of thousands of people who, by definition, aren't geniuses...people are weird).

Re: If Richard Feynman applied for a job at Microsoft (2002)

#163

Post by RHSeeger »

thom wrote: post #8
cableshaft wrote: post #3

I was expecting something a little different, where they passed on him because he didn't give the 'right' answer (what the interviewer had preconceived and/or looked up online).

Well, that _is_ the conceit here. The ‘right’ answer is that all manhole covers are round because a round cover can’t fall into the hole.

But a triangle works for this, too.

Re: If Richard Feynman applied for a job at Microsoft (2002)

#164

Post by hintymad »

memco wrote: post #147
hintymad wrote: post #120

Earlier quoted context omitted.

I'm not sure I buy this type of attack. How is this different from calculating yield of a bomb as Fermi did? It's back-of-envelope calculation that physicists do all the time. Ping Pong in a Boeing is merely a setup with the least context. This is like criticizing a math teacher for asking elementary students to calculate how long it takes to fill a swimming pool when water is flowing in and out of the pool at the sa…

Why use the pool at all if you already have useful examples of inflow and outflow of money or another or the queue at the grocery store? Someone of age to understand flow rates of liquid would likely be able to understand money enough to be able to do the same calculations can’t get the same principles but with a functional analogy instead.

My guess is that such problems are for 3rd-graders, who do not necessarily have real-world experience to understand more realistic setup.

Re: If Richard Feynman applied for a job at Microsoft (2002)

#165

Post by HarryHirsch »

prionassembly wrote: post #153
LeifCarrotson wrote: post #55

Earlier quoted context omitted.

I'd never seen that before, that's excellent! The original PDF is at https://www.unz.com/PDF/PERIODICAL/SaturdayRev-1968dec21/62/ , which is includes a nice drawing of the student speaking with a building superintendent while holding a barometer, but to say more would be to spoil the punchline. Here is the text: > Angels on a Pin By ALEXANDER CALANDRA SOME time ago, I received a call from a colleague who asked if I w…

Interesting. Unz.com is a radical Right (I wouldn't say extreme-right) wing website...

They have a dualistic world view, and the public school system is part of where the enemy stands. Anything that scores points against the enemy is a good weapon.

Re: If Richard Feynman applied for a job at Microsoft (2002)

#166

Post by AnotherGoodName »

okareaman wrote: post #75

How many ping pong balls would it take to fill a 747? Why do you ask? What problem are you trying to solve? We want to understand your thought process I'd think it was stupid to fill a 747 with ping pong balls and think about something else

Feynman wouldn't dismiss that question. He'd overthink it.

Someone once asked Feynman which way a top spinning sprinkler would spin if it was underwater and water was sucked through it instead of pushed out of it. He got into back and forth debates with other students. He ended up using the universities cooling pond for the cyclotron to actually run the experiment.

https://en.wikipedia.org/wiki/Feynman_sprinkler

So if you asked Feynman "How many ping pong balls would it take to fill a 747?" you wouldn't receive a "Why do you ask? What problem are you trying to solve?". Instead you'd find him trying to acquire a large 747 and a whole lot of ping pong balls in order to validate his initial guess.

Re: If Richard Feynman applied for a job at Microsoft (2002)

#167

Post by thinkharderdev »

derekp7 wrote: post #138
hintymad wrote: post #120

Earlier quoted context omitted.

I'm not sure I buy this type of attack. How is this different from calculating yield of a bomb as Fermi did? It's back-of-envelope calculation that physicists do all the time. Ping Pong in a Boeing is merely a setup with the least context. This is like criticizing a math teacher for asking elementary students to calculate how long it takes to fill a swimming pool when water is flowing in and out of the pool at the sa…

This is fine if the question relates to something that the candidate is familiar with. But I have personally never set foot in a 747, much less be able to come up with any estimate of the dimensions in order to estimate volume. Then there is the formula to determine the packing volume of ping pong balls. Just like the question of how much water dumps out of the Amazon river per day. Yes, I can write down a formula wi…

How well these questions correlate to job performance is an interesting question but the goal I think is not for you to get to the "right" answer (in the sense of figuring the optimal bin-packing approach on the fly). The goal is to see how you are able to take a broad problem and break it down by:

1. Identifying key assumptions or inputs. You may not know the dimensions of a 747 off-hand but ideally you can come up with a way of determining the number of ping-ping balls GIVEN the correct dimensions as input. That is you can come up with a model that you can plug the right numbers into once you look them up.

2. Clarifying the problem by asking questions and drilling in on requirements.

3. Create a model that you can communicate to others and allows you to make decisions just based on order-of-magnitude considerations. I.e. make decisions under uncertainty.

All of those skills I think are relevant to software engineering and system design. For example, you may need to provision hardware long before you know the exact design of a system. Can you come up with a rough estimate of how much storage you will need? Or at least put reasonable upper bounds on it? How many qps would you expect a system to need to support and does that mean you have to use a distributed datastore vs a single RDBMS?

Re: If Richard Feynman applied for a job at Microsoft (2002)

#168

Post by thinkharderdev »

flavius29663 wrote: post #149
deanCommie wrote: post #135

Earlier quoted context omitted.

The real problem with that question isn't that it's stupid. Everyone knows it's stupid, it's testing your ability to come up with an estimate in a domain you're not too familiar with using "napkin math". That's a legitimate skill and asset in software engineering. The real problem is that the ability to come up with a good napkin math estimate for a technical problem doesn't correlate with the ability to actually do…

Which is why companies started moving into other questions that have no relation to your job, like designing youtube. There is such a slim chance that you'll end up designing youtube at your tenure there, in a team of 2...that it's probably more likely to fill a jet with balls. Yet somehow people are not bothered by the design youtube question the same way they are about balls in a plane. It's true that the youtube v…

Yeah, I think in general people lump Fermi estimation problems in with "brain teaser" questions (which I think really are silly) because they are both technical(ish) interview questions that have nothing to do (superficially) with software engineering.

Re: If Richard Feynman applied for a job at Microsoft (2002)

#169

Post by version_five »

mabbo wrote: post #157
conjecTech wrote: post #143

Earlier quoted context omitted.

I don't get the derision for these kinds of problems. And I think it's unlikely Feynman would have found this unhelpful. These are commonly referred to as Fermi problems. Fermi was a physicist of Feynman's generation - they were probably standing together at Trinity when Fermi did the famous yield approximation. The other physicists held this ability in such esteem they gave it a name and remembered him for it. The q…

The 747 ping pong ball estimation problem is a Fermi problem, where the goal is to get the right order of magnitude of the answer. Sure. But "why are manhole covers round?" is not. It's a stupid "have you ever heard this clever fact" question that's often designed just to figure out if you're clever and/or lucky vs testing actual knowledge and skill. If your aim in interviewing is to fill the team with people who lov…

I worked and interviewed a lot of people in business consulting. We did ask what you call Fermi problems as they are surprisingly representative of the abstract thinking that is required in the job, specifically proposing frameworks for what kind of information we need to either go and get or state as assumptions in order to support a decision. As the GP points out, the questions are testing how you model something you don't know but have common sense about, and significantly, how you don't get caught up in uncertainty or irrelevant minutia and identify some core assumptions.

That said, I agree 100% with you about "trick" questions. It seems some people cannot distinguish between "market sizing" (Fermi problems) where you need to make reasonable assumptions and describe a model of something, and "a man is found in scuba gear in the middle of the forest" brainteasers for kids. I have no idea why anyone asks brainteasers in an interview.

Re: If Richard Feynman applied for a job at Microsoft (2002)

#170

Post by zem »

ThePadawan wrote: post #38
cacois wrote: post #30

Earlier quoted context omitted.

You were supposed to expect them to fail his interview because he didn't give the "right" answer (manhole covers are round so they can't fall in the hole). Instead, he completely disagreed with the "right" answer, but did so in a way that was incredibly convincing. So, they decided his primary value was not in his intellect (leading him to a job in engineering), but in his ability to convince people of things (leadin…

I did follow the "intended" vs. "right" subtext right until the punchline. I also at no point got the impression that this fictional Feynman was very convincing, charming or anything like that. Just a bit of a talky wise-ass, really. Obviously he knows his stuff, but he's not direct enough to just say that outright, he tries to lord his intellect over the interviewer. So I really wasn't sure what the punchline ("let'…

yep, the joke was getting at the "talk lots and lots of bullshit" aspect. it's the engineer's stereotype of a marketing person. like, "hey, this guy won't cut it as an engineer - he couldn't even answer the manhole question. but he sure can spout bullshit with the best of them!"
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