Case

# Brain Teasers - Firefighter

Solved 3.7k times
Difficulty: Intermediate | Style: Brain Teaser | Topics: Brain teaser

## Problem Definition

### Firefighter

Situation:

A firefighter stood on the middle rung of a ladder, spraying water on a burning house. He then climbed up 6 rungs before the heat of the flames caused him to come down 10 rungs. After some minutes he was able to climb 18 rungs to the very top of the ladder.

Question:
How many rungs did the ladder have?

### Bartender

Situation:
There are two twin old men that go into the same bar every day. The bartender at the bar hates one of the twins, but there is only one way he could tell the difference between them: The one that he hates drinks very slowly and the one that he likes drinks fast.

One day the bartender decides to kill the one that he hates. So when they came in that day he put the same amount of the drink in their cups, the same amount of ice, and the same amount of poison. When they are both done with their drinks the one that the bartender hates dies, but the one he likes lives.

Question:

How is this?

### Hats

Situation:
There are 4 people sitting in a row, trying to win a riddle.

• The one in front was wearing a red hat.
• The second from the front was wearing a blue hat.
• The third from the front was wearing a red hat.
• The last was wearing a blue hat and is blind-folded.

Each of them was informed that they are all wearing a hat, the last person is blind-folded and that there are 2 red and 2 blue hats. They can only see the persons in front of them and are not allowed to turn around and see behind them.

Question:

The one who guesses the color of his hat wins the prize. Who is it?

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.

## Detailed Solution

### Firefighter

29 rungs

The firefighter is standing on the middle rung. He goes up 6 rungs so he is now at M+6, he now goes down 10 rungs so he is now at M-4 he goes up 18 rungs so he is now at M+14=T. 14 rungs from the top, 14 rungs from the bottom and the middle rung. 14+14+1=29

### Bartender

The bartender puts the poison in the ice.

In the drink of the one who drank slow the ice melted, but since the other one drank fast, his ice never melted.

### Hats

It was the second person.

The first and last person cannot see other people at all, therefore it is either the third or second. The second person realized that if he and the person in front were wearing the same colored hat, the third person would be able to answer the color of his hat right away. However, since there was a long silence, then the color of his hat and the person in front must be different.

## Difficult Questions

Related consulting question(s)

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 ev... (more)

Hi, good question! Probably somewhat depending on your interviewer, but this is my view on it. In this situationit's important to try to showcase as mluch of your consulting skills as possible. Be t... (more)

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)

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)
4.4 (46 ratings)
Case exhibits

No case exhibits yet