"How much would you charge to clean every window in London?"

megakid

megakid

megakid

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A friend just said that was one of his questions in his final round Google interview.

How would you go about it answering it?
 
"I wouldn't go round cleaning every window in London because I have more productive things to do, such as having an interview with a large internet company that has better job prospects".
 
apeZ said:
"I wouldn't go round cleaning every window in London because I have more productive things to do, such as having an interview with a large internet company that has better job prospects".
Click to expand...

*puke*

£10 per window, and then subcontract the work.
 
50p per window and pay some people minimum wage to do it for me. Assuming they can do 14windows a hour i should be able to turn a profit.
 
I have no idea what answer they expected. From the sounds of it, they didn't give him much of an indication either.

I'd definitely ask the "inside and out?" question which is a good one to start. Remember the question is how much would you charge, not how you would go about doing it. It's tempting to dive into the numbers i.e. number of windows per building, number of buildings etc etc but I have a feeling this wouldn't be what they're after.
 
As a stylistic answer:

Population of London is ~10m, assume average household size of 1.75 people, implying about 60 buildings/houses per hundred, but round up to eight per person to take into account commercial/state buildings. Estimate an average of fifteen windows per building gets you:

10,000,000*.8*15 == 18,750,000 windows

Estimate that it would take, on average, fifteen minutes to clean a window (including time moving between windows) and require five pence in materials (ignore start up costs for the time being). As window cleaning is a low-skill job, use labour cost of £6.00 (£5.80 rounded up to six to take into account national insurance etc.), therefore your cost per window is:

0.05 + 6.00*(5/60) == 1.55

This takes your total variable cost to

18,750,000 * 1.55 == 29,062,500

Then you could make an allowance for the fixed costs required (admin etc.), say £100,000, taking you to a total cost of 29,162,500. Then add a profit margin that you find acceptable and you're home dry. Let's say £35mil total :)

Obviously I've done some heavy guestimation here, but the exercise is about seeing if you can think through the problem. Also a good idea is to use numbers that sound sensible but will make the maths easy - notice that you shouldn't need a calculator for this answer*.

EDIT: Thanks to Darg for pointing out the maths fail. * You will now, I'm too lazy to change the assumptions.
 
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I'd make a website on which people could upload pictures of their dirty windows.
An automated program could alter the images to make them 'clean'.
Users could even print out a picture of their electronically-cleaned windows.
The website would be self funding through advertising!
Do I get the job?
 
What would be awesome, is to know the exact stats already.

"How much would you charge to clean every window in London?"
"Well considering there are 352 million windows in the greater London area, and assuming that windows are to be cleaned only on the outside only.. etc..
:eek:
"Right.. we've err never had that answer.."

edit: bah.. Seft ruined my response!
 
A question like that obviously isn't after a straight '£xxxx' answer. I think something along the lines of: "I would charge nothing, but the deal would involve placing an advert on every window." is probably along the right lines.
 
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