Brain Teasers - Barbershop

Solved 3.8k times
4.1 5 25
Difficulty: Intermediate | Style: Brain Teaser | Topics: Brain teaser

Problem Definition


A business man is in a village for a meeting. He has time to spare before the meeting, so he decides to get a haircut. He looks at a street map and was surprised to find that there are only two barbers in town, right across the road from each other.

He went into the first one and was shocked by the dirtiness and the hair everywhere. The place was a mess! He looked at the barber and the barber had a really messy haircut, all in his face and uneven. He went across the street to the other barber and saw the place was immaculate, clean and shining like new. The barber was nicely dressed and had a dazzling haircut: it was perfect. However, the man walked across the street and got his haircut at the shabby barbers.




Two rivalling islands Blueria and Redania have ever since been fighting about what the best color is. The only connection between the islands is a bridge, which is guarded by a security guard on the Redanian side, who would come out every three minutes and check on the bridge. He has instructions to deny access to everyone coming from Blueria and spray everyone with red paint who is trying to escape from Redania to Blueria.

A Redanian woman that loves the colour Blue desperately wants to live in Blueria. Being covered in red paint is not an option. She knows that she will at least need six minutes to walk across the bridge.

How did she manage to live in Blueria?


Brain Teasers are short questions with difficult logical or creative answers. They are a good way to test your analytical skills and capacity to think out of the box. These short questions also show the interviewer your ability to elaborate on difficult tasks from the real world. Each Brain Teaser is supposed to be solved by the interviewee in about 5-10 minutes.

If the interviewee gets stuck in a brain teaser (i.e. spends more than 10 minutes), propose to go on to the next one.

Short Solution

Detailed Solution


Since people can't cut their own hair and there were only two barbers in town, the two barbers must have cut each other's hair. So, the poor haircut must have been performed by the clean barber. Therefore, the good haircut must have been performed by the messy barber in the first shop.


She walked on the bridge towards Blueria for 3 minutes and just as the guard was about to come out, she turned around walking back to Redania. The guard saw her and sent her back (or what the guard thought was back) to Blueria. In her case it was the very island she wanted to go to.

Difficult Questions

Related consulting question(s)
Best answer so far:
Ex BCG | MBB Specialist | #1 Expert for meetings done (1100+) and recommendation rate (100%)

Hi Anonymous, there may be several reasons for that; some of them, in order of frequency, are: Your structure is not complete enough – you are just using not MECE/ not complete structure... (more)

Hey, I am new to this too, but I think I have some ideas for your problem. Your approach looks good, but I think you have a mistake in how you time the trains. You say that there is one train e... (more)

Best answer so far out of 3 answers:
Two years conulting experience, went through lots of interviews and coached several candidates to MBB offers

Hi, good question! Probably somewhat depending on your interviewer, but this is my view on it. In this situation it's important to try to showcase as mluch of your consulting skills as possible. Be... (more)

Best answer so far out of 2 answers:
Specific coaching: company you are applying for; 1st or 2nd round; your professional background; ...

Hi, here's how I would approach it - Define the geographic area to be covered [the whole world? the U.S.? NYC? Manhattan?...for this example I'll use Manhattan] - Population living there [~ 1... (more)

Best answer so far out of 3 answers:
McKinsey / Accenture / Got all BIG3 offers / More than 300 real MBB cases / Harvard Business School

Hi, First of all, I totally agree with Francesco on the process. You should always come back to the cases you've solved and reevaluate your structures. Secondly, I believe it's very much related... (more)

Related BootCamp article(s)

Typical Question Types in Written Tests

Questions among all tests can be categorized in math, GMAT-style, chart reading and brain teaser questions. Each type needs to be approached differently.

4 Comment(s)

Brain Teasers

Learn how to tackle brain teasers and what purpose they serve in consulting case interviews

2 Comment(s)
4.1 (25 ratings)
4.1 5 25
Case exhibits

No case exhibits yet