Bain & Company Interview Question: Estimate how many windows are... | Glassdoor

Interview Question

Associate Consultant Interview Boston, MA

Estimate how many windows are in New York


Interview Answer

34 Answers


Divide and conquer. I may not know the answer to the question, but I can determine the answer because I can approximate two supportnig questions:
* How many people are in New York (City or State, btw)
* How many windows, on average, does each person have (home, car, work, shopping center, ....)

I'll say 10M in NYC and 10 windows per person so my answer is 100M windows in NYC.

Bill on Aug 17, 2012

10 windows per person?!?! I want to see what apartment you're living in!!

Kim on Aug 20, 2012

he said 10 windows per person total (including car, home etc).
10 makes good sense.
However, i do believe you'll have to go deeper than that.
i.e- calculate that, add businesses, shopping centres, cabs and passing cars etc.

raphael on Aug 30, 2012

I would have said , "if you hire me, I'll get my team on that right away."

Jonathan Schlackman on Jan 11, 2013

Not everyone in the city has a vehicle, so 10 per person can't be the basis of calculation.

AB on Jan 11, 2013


Kaushal Chawda on Jan 13, 2013

Define "New York".

SoCal on Jan 17, 2013

Should the answer include opportunities and operating systems?

Rich on Jan 17, 2013

There is an N, e, w, a Y....nope, no windows

SMB on Jan 17, 2013

Since Bain is a consulting firm, this question seems to be used as a way to probe applicant's approach to engagement problems.

First ask questions to clarify the goal. Is New York the city, the state, or another municipality that happens to also be called New York, such as New York, Texas. Are we talking about windows on a building, or will it also include car windows, store shelf windows, or maybe even MS Windows licenses.

After the information is clarified, it's time to analyze. Estimating the population and estimate an average number of windows per person is one approach, but it may seem too general. Another approach can be divide and conquer. Estimate the number of residential houses, estimate the number of offices, and number of vehicles, etc, and multiply by an average number for each type of structure. Round the number to the nearest million or tenth of million to make it easy to remember for the client.

John on Jan 17, 2013

I don't do windows, sorry

KT on Jan 18, 2013

I gather that this very important question has some significant meaning to you, and I feel you should hire me to get to work on the answer right away. I'm going to need some support staff for this, and a travel expenses budget, and a small but dedicatd team of window counters. Gosh, see how when you ask me a question of genuine importance, I get all fired up?

Jim on Jan 18, 2013

"call Microsoft"

Ed on Jan 22, 2013

Four, the answer is four.

Bill on Jan 23, 2013

Seriously?! No.

matthew on Jan 23, 2013

Simple, all of them.

Robby on Jan 23, 2013

If you are going to estimate correctly, you need to come up with a range. A single point estimate is pretty much guaranteed to be wrong. No matter which approach you take (average building floors by average number of windows, people * number of windows, etc), at best you get a midpoint of a range. The question is how wide does the range need to be? At this point, with little information, you need a pretty wide estimate (in the million window + range).

Greg Beamer on Jan 23, 2013

Exactly why I was thinking of Corning as a great Private Equity deal! Let me explain...and let's take this one step further...let's start with the Eastern Seabord, and the number of windows that are really hurricane let's look at the advantages of Gorilla Glass, it's uses, and strategic opportunities...let's go bigger than New York!

Tim Pilon on Jan 24, 2013


Cheeky Monkey on Jan 24, 2013

as many as the glasses..

pankaj on Jan 24, 2013

new y " O " rk. only one window.

naveen varada on Jan 24, 2013

I personally don't have the answer but I will find out and get back to you. When do you need to have a response?

Julie on Jan 25, 2013

windows 8

neha jagare on Jan 27, 2013

do i include window's on every1's computers monitor or laptop for this?? if so then 10 windows per person at instant will be less caz the question is not clear at all,

Chirag Sarang on Jan 27, 2013

only one microsoft windows

Raja sekhar on Jan 29, 2013

more than door............

sukhdeep on Jan 30, 2013

1 window compulsory = no. of houses in NY

nilesh manjavkar on Feb 3, 2013

There are 271,925,321 windows.
If there are more windows then it would have been made after the survey and if it is less, then it would have broken down.

Pranay Shah on Feb 4, 2013

Are you talking about glass pained windows? Do double pained windows count as two or only one. Should I include MS Windows? What about the number of windows the average person has open at any one time? Which version of MS Windows? Are we talking both server and desktop versions of Windows?
I know the answers to all of these questions, but I need to know which ones you want included in the answer. Then (if you have some paper) write some numbers down, do some calculations and give them an answer of some big number that is based on the calculations you made.

(This is a question where they are trying to see if you can think outside the box and come up with some sort of reasonable estimate. There is no right answer that can be acheived or verified.)

Ken on Feb 14, 2013

There are no windows for new york because it is a city not a house to provide windows

kumar on Jun 3, 2013

@Bill: you forget '2' the after the '4'

michou on Jun 4, 2013

People 50m=dwelling x 5 windows =250million

Anonymous on Mar 7, 2015

What size is your window dimensions ? Large commercial could equal 4 residential size windows. Do you consider single pane or double glass as still one window ? What about glass block windows, do they count ? Like Carl Segan used to say, billions and billions...

Wray - Denver on Feb 3, 2016

When I think about this question I would want to simplify the categories into Residence windows and Business windows (other types exist but this should cover a large majority of standard construction windows).

Starting with residency, I'll assume ~15M New York population, with roughly 80% in apartments and 20% in homes. Of the apartments I'd go with an average occupancy of 2, and home of 3. Then thinking about how many windows are in typical rooms in each residency (bedroom, dining, kitchen etc.) I came up with 14 windows in homes and 5 in apartments. Multiplying the numbers correctly I came up with 30M apartment windows and 14M home windows.

Then for business windows, I decided that an appropriate number would be 80% of population is working, 20% with their own office which has one window. The other people are in shared work spaces, which I will assume on average have half as many windows as people. When multiplying these correctly I got 7.2M business windows.

Total I ended up at 51.2 M windows.

Anonymous on Oct 14, 2018

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