Google Interview Question: Choose a city and estimate ho... | Glassdoor

Interview Question

Product Manager Interview New York, NY

Choose a city and estimate how many Piano Tuners operate a

  business there.

Interview Answer

6 Answers


Made some assumptions, seems with these its best to make an assumption rather than ask a question and check with them that the assumption is ok

Interview Candidate on Apr 20, 2015

Chernobyl - Zero

Soheil on Jun 19, 2015

Oh no - are they still asking the piano tuners question! :-( Arghhh..

Anonymous on Jun 26, 2015

This is a Fermi problem- search for fermi problems for answers

Anonymous on Jan 29, 2016

Let's choose a city, say Los Angeles. Let's start with the population of Los Angeles. I know that New York has a population of 5M. I'm going to assume that Los Angeles is roughly the same (although its probably smaller). Let's go with 5M inhabitants.

5 * 10^6 inhabitants.

Now lets start making some assumptions.
1) I know that roughly 3 people occupy each home. So we can assume that in LA there are roughly 5/3 * 10^6 homes.
2) Not all homes will have a piano. Lets assume that 10% of homes will have a piano. This will result in 5/3 * 10^5 pianos.
3) Now a piano tuner can probably tune 1 piano a day. I don't know what tuning is but maybe that's reasonable? That means, a single piano tuner will be able to tune 300 pianos a year
4) Now, how many tunings does a piano need per year. Once again 1 sounds reasonable.

lets put it all together. To guesttimate the number of piano tuners, all we need is # of tuning opportunities per year / # of tunings per tuner per year.
= 5/3 * 10^5 / 300
= 5/9 * 10^3
= 550 piano tuners that can be gainfully employed.

This number seems reasonable :)

Sparthan on Jul 16, 2016

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