13 Brain-Melting Questions That Companies Ask During Interviews

Though Google reportedly banned mercilessly difficult brainteasers from its interviews and admitted the questions were useless to begin with, there are companies that continue to test their candidates' mental strength with crazy questions, according to Glassdoor.com users.

Whether they test market-sizing knowledge, creativity, or stress-control, these questions could make anybody sweat.

Microsoft: How many gas stations are there in the US?

Senior Program Managers at Microsoft are expected to be able to conduct market sizing on the fly, as of June 2013.

How might one answer this question? Start by estimating how many gas stations might be in a town of around 30,000 people, and then extrapolate for the U.S. population, which is about 314 million people.

It turns out there are upwards of 117,000 gas stations in the U.S. According to the U.S. Census Bureau, in 2008 there was one gas station for every 2,500 people. 

IBM: How would you test a calculator?

IBM asked software engineer candidates this question as recently as May 2013. 

It's a vague question, with little direction and little context. It's really about the details here.

You might provide this type of response:

Test the functionality of the calculator's computing accuracy by evaluating whether inputs provide their expected outputs. Also, test the device's basic system functions — like the power button, the clear function, and so on, to determine whether you'll be facing system errors before you can compute anything. 

Depending on the position for which you're interviewing, you may have to delve deeper into the world of calculators. 

IBM: How many golf balls are there in Florida?

IBM threw their operations specialist wannabes this market-sizing question during May 2013 interviews.

To get an answer, you might start by estimating the U.S. population, then the percentage that plays golf, then the number of balls each player users in a year. Then estimate what percentage of U.S. golfing occurs in sunny Florida. Then toss in an extra 50% for old or unused balls.

BrainTeaser Bibles used a similar method to estimate that there 2 billion golf balls are used in the U.S. each year, to which we'll add 1 billion in old or unused balls. Seeing as 7% of America's golf courses are in Florida, we'll say there are 210 million golf balls in Florida.