Answering 25 tough interview questions, part 1

I stumbled across this blog post listing 25 tough interview questions that people have been asked, and thought it might be rather jolly to attempt some answers. I’ve not read the questions before embarking on this process, so I have no idea whether they’ll be interesting or not, but I feel the need for some light relief after recent work.


I’ll take them in batches of five. Here are the first five:

1. “If you were to win £1 million what would you do with the money?” – Asked at PwC.

Half for me, half to do some good in the world.

I’d need to invest some time to find the best charity or charities to dump £500k on in a way that didn’t completely distort the way they work. I could imagine myself using some of that money to fund scientific projects that I care about — for example, palaeontological digs in areas that could turn up sauropods. But the bulk of that half would probably go on third-world charities of some kind, maybe a rolling portfolio of micro-investments. I’d probably need to hire a consultant to figure out the details for me, so that would take a (hopefully small) slice out of that half.

As for my half: £160k to pay off the mortgage, £200k to prime the pension that I shamefully only started a few months ago. £20k to sort the house and garden out. Put aside £27k each to pay the boys’ university tuition fees, for a total of £81k (ouch!) That comes to £461k, which leaves me £39k to play with — holidays, electronics, guitars and so on. Seems about right.

I certainly wouldn’t stop work — I love it. But I might consider winding down to four days a week, or at least buying an additional two weeks of vacation days each year.

2. “What do you think is the most useful function in Excel?” – Asked at FirstGroup.

Honestly? It’s great for editing tables. That’s what people use it for, right? Much more often than they do for actual calculations, far less the complex “what if?” scenarios that they sold VisiCalc on back in the day.

I wonder whether spreadsheets are due for a radical rethink? They were a true novelty back in 1979, then underwent a real reinvention with the first GUI versions of Excel, but have stagnated badly since then. What would a genuinely useful dynamic calculator look like in 2013?

(Fun fact: I once implemented the game of Hunt the Wumpus in Lotus 1-2-3. It would have been about 1985, and I was supposed to be doing a part-time data-entry job for Pitney Bowes, but they didn’t have anywhere near enough work to fill my time. Come to think of it, I am not 100% sure that I didn’t use actual VisiCalc for this.)

3. “What makes you happy about work on a Friday evening?” – Asked at Tesco.

The weekend. I enjoy work, but I also enjoy not-work, and I particularly enjoy the transitions between them. However good it’s been working for the last five days, I enjoy the prospect of spending the next two with my family.

On the boundaries between Work and Other: this is one of the reasons why I don’t have a mobile phone. (Well. I have a pay-as-you-go Nokia 3510i, which I bought in 2005, but I never turn it on. I only have it so I can call home when I am on business trips.) When I am on a computer, which is nearly all of my office hours, I am obsessively in touch — always with email, Twitter and Skype running. It’s important to get away from that sometimes, and I don’t trust myself to be able to do that if I had a smartphone.

4. “How do you fit a giraffe in a fridge?” – Asked at UBS.

An easy one: you can’t. An adult giraffe weighs upwards of a tonne. Like all mammals, it’s roughly as a dense as water(*). That means its volume is greater than 1000 litres, and a fridge is much smaller than that. A bit of googling suggests that a typical fridge-freezer has a capacity on the order of 200 litres. So if you really want to refrigerate a giraffe(**), you’ll need to buy five fridges, mince the giraffe, and stuff the mince into the fridges. Use an industrial-grade mincer than can cope with the bones.

(*) My academic colleague and occasional co-author Darren Naish co-wrote a paper on the floatational dynamics of giraffes, so I know whereof I speak.

(**) Another academic colleague, the biomechanics wizard John Hutchinson, has all sorts of dead animals on ice at the Royal Veterinary College. His blog What’s In John’s Freezer? has a whole category on giraffes. So another answer to the original question would be “delegate to the RVC, who have expertise and experience in this field”.

5. “What is it about this job you would least look forward to?” – Asked at BP.

If it was asked at BP, then I suppose the answer would be being associated with a company that is primarily known for being responsible for the worst man-made ecological disaster of recent years.

But taking the question rather more generally, I would miss the friends and colleagues I have in my current job. I work somewhere where we carry no passengers: everyone at Index Data is clever and interesting, and I’d be unrealistic to expect that at most other companies — especially if it was somewhere big like BP.

On the positive side: I’ve only ever had three real jobs (which I held for nine years, three years, and ten-and-counting years). On both the previous times I’ve changed jobs, one thing I really did enjoy was no longer being responsible for the support of all the stuff I’d built over the years. There is something intoxicating about the clean slate of a new job, of owning no code yet.

OK, those are my answers. How about the rest of you?

12 responses to “Answering 25 tough interview questions, part 1

  1. 1)”Be out of here so fast I’ll be seeing the Doppler effect.”
    2)”IF(), and assorted levels of nesting with AND() and OR(), because such incredibly baroque and impossible to read equations are job security.”
    3)”Knowing it’s almost over.”
    4)”Get a large fridge, or a small giraffe.”
    5)”Being polite to people at office parties.”

  2. 1) Capital. I think we’re poised to fundamentally re-invent a lot of aspects of computer animation, but we’re a small shop, and it is molasses-slow. I’d upgrade my lifestyle a little bit, but mostly I would invest it in the business, and maybe other businesses.

    2) I have no idea. The last time I did anything in Excel was years ago when a housemate who worked for a large insurance company asked me to help her script some things in it. I think vbscript gave me a venereal disease.

    3) I don’t generally work on Friday evenings. There’s only a certain amount of code in me in a week, and it is all used up by Friday evening.

    4) If someone asked me this at a job interview and I did not really need the job I would likely leave. I’ve solved some difficult and long-standing _actual_ problems, and the results are public. I am not interested in trying to fit a giraffe in a refrigerator. If I really needed the job and wanted to follow your tack I would suggest dehydration. Otherwise I would suggest getting a very large refrigerator.

    5) I’d have to know more about the job… but I don’t imagine there are a lot of positions I would apply for at BP.

  3. If I really needed the job and wanted to follow your tack I would suggest dehydration.

    Surely that’s cheating? You’re not putting the whole giraffe in the fridge? If you’re allowed to eliminate the water, then what’s the limit? Can you dump the blood? The skin?

  4. Well, since the giraffe could be reconstituted later, I think it’s functionally equivalent to the original problem ;).

  5. Andrew Hickey

    1) Half to charity (the Against Malaria Foundation, who according to are the charity that lets you save most lives per pound donated — I give regularly to them partly because of that, and partly because I hate mosquitos). Then spend £100,000 or so on a small house, stick the rest in the bank, and become a full-time writer, living off my writing earnings and the interest, which would be more than enough without any rent to pay.

    2) File -> Exit.

    3) Same answer as you, right down to not having a mobile phone, for the same reasons.

    4) Get a baby giraffe. Or a huge refrigerator.

    5) Probably the office hours (I work best at night) or the office itself (open-plan offices are evil).

  6. How to fit a giraffe in a fridge: We will assume the fridge is currently full, so first, remove a pot of strawberry yoghurt from it. Next, recall that the volumes of the yoghurt pot and the giraffe are both non-empty bounded subsets in 3D Euclidean space, and hence equidecomposable according to standard set-theory. With this insight, and following Banach-Tarski, carefully dissect the giraffe into a finite number of pieces and then reassemble the pieces in such a way as to recreate the shape and volume of the yoghurt pot. Finally, place the reassembled giraffe in the fridge.

  7. Pingback: Answering 25 tough interview questions, part 2 | The Reinvigorated Programmer

  8. Pingback: Answering 25 tough interview questions, part 3 | The Reinvigorated Programmer

  9. Pingback: Answering 25 tough interview questions, part 4 | The Reinvigorated Programmer

  10. Pingback: Answering 25 tough interview questions, part 5 | The Reinvigorated Programmer

  11. “4. “How do you fit a giraffe in a fridge?” – Asked at UBS”

    According to page 1 of World Animal Foundation’s Giraffe Fact Sheet, a fully developed male giraffe can “weigh between 2,400 and 3,000 pounds”. The question does not specify a type of fridge nor does it set a limit to the fridge’s dimensions. Page 23 of the Federal Highway Administration’s Comprehensive Truck Size and Weight Study Volume 2 Chapter 3 says that with 48-foot refrigerated trailers “and properly specified tractors, carriers can routinely handle 46,000-pound payloads”. So my question is… do you really only want one giraffe?

    Click to access giraffe.pdf

    Click to access Vol2-Chapter3.pdf

  12. You’re awesome

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