Ask HN: What are the hardest verbal interview questions you've faced?
What are some of the hardest technical questions you've been asked during a verbal/on-site interview? And how did you go about answering them? Please note the type of job you were interviewing for.
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I'll start:
(This was for a full stack engineering role:)
Q: "What is the radius of the earth? Give me an answer and walk me through how you got there."
A: I had no idea. I figured that SF to NYC was roughly 3,000 miles and that was 4 timezones. The whole earth is 24 timezones so I multiplied by 6 to get the circumference of 18,000. Since the circumference is Diameter * Pi I divided by 3 to get a diameter of roughly 6,000 and divided by 2 again to get the radius of 3,000 miles.
I googled the answer after the interview, I was off by about a thousand miles. Not bad.
2 comments
[ 5.6 ms ] story [ 13.3 ms ] threadQ: where do you see yourself in 1 / 2 / 5 years?
A: The last couple jobs i've answered with "I'd like to find myself in a management / leadership type of roll - I know enough about technology / what my industry (programming) does and operates that I think I'd be a great project manager". I've yet to accomplish this; i'm still a full stack developer (albeit, making good money) but I have yet to break into management at a day job.
If I get asked this in the next job my answer will most likely be "I have no idea. I don't want to say "well see where the wind takes me" but the technology landscape changes to quickly and to frequently to make any educated guess as to where it'll be in 1 / 2 / 5 years - and as a developer, you need to go where technology goes. 8 years ago, I was a systems administrator; 5 years ago, I was writing almost exclusively in PHP. This year, it's almost all AngularJS and NodeJS. I'll know where I'll be tomorrow when tomorrow comes."
or something like that.
BTW, there are three factors that affect your calculation which you left out. First, the fencepost error. While SF and NYC have two timezones in between, neither city is on the furthest edge of its timezone. With better knowledge, an estimate of 3.5 is more correct, giving (24/3.5)3000/(2 pi) = 3274 miles.
Second, 3,000 miles is the driving distance, not the great circle distance, which is only 2,500 miles. (24/3.5)2500/(2 pi) = 2728 miles. Still, I think 3,000 miles is good for the ballpark estimate you made, and it's certainly not a fact I have at hand.
Third, those two cities lie at about 40 N latitude, so you computed the length of that latitude, not the length of the equator. You need to divide by cos(40 degrees). cos(45 degrees) is sqrt(2)/2 = 0.707, so I'll use 0.75. (24/3.5)*2500/(2 pi)/0.75 = 3637.