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Brainteasers are another kind of question that you might confront in consulting interviews.

They are likely to be tricky and to require “out of the box” thinking.

Why do interviewers ask brainteasers?

Well, since clients can sometimes ask questions which have no immediate or obvious answer, the goal of the brainteaser is to assess how well you deal with ambiguity under pressure.

Here is a list of six (6) sample brainteasers to give you an idea of what you might come across in your consulting interview (answers will be posted next week).

- Why are manhole covers round?
- There are 6 blue socks and 6 purple socks mixed randomly together in your sock drawer. It is dark, and you cannot tell them apart. What is the smallest number of socks that you need to take from the draw to be sure you have one matching pair?
- Is there anything interesting about the following sequence of numbers? 8, 11, 5, 4, 9, 1, 7, 6, 10, 3, 12, 2, 0
- You have three boxes of eggs. The boxes contain (1) big eggs, (2) small eggs, or (3) a mixture of big and small eggs. The boxes are labelled: Big, Small and Mixed but every box is labelled incorrectly. What is the least number of boxes that you will need to open to know which eggs are in which box?
- You invest $100 today in a company. The share price goes up 10% in the first year but then drops 10% in the second year. At the end of the second year do you have more, less or the same as you started with?
- You are driving a bus and tracking the number of passengers on the bus. At the first stop, the bus picks up 22 people. At the second stop, 15 people get off the bus and 8 new passengers get on. At the third stop, 5 passengers get off, and 13 new passengers get on. At the fourth stop, 5 passengers get off, and 2 get on. What is the color of the bus driver’s eyes?
- In a tiny cabin in the woods, two men lie dead. The cabin is not burned but the woods around it have burned. How did the men die?
- You are the owner of a pet store. You have a number of canaries and bird cages. If you place one canary per cage, you have one bird too many. If you place two canaries per cage, you have one cage too many. How many cages and canaries do you have?
- Mary’s father has five daughters: Nana, Nene, Nini, Nono, and what is the name of the fifth daughter?
- A rich father is dying and wants to leave his properties to his wisest son. He asks them to purchase something that can fill the bedroom, but is small enough to fit in their pocket. What did the wisest child bring?

[For more information on consulting interviews, please download “The HUB’s Guide to Consulting Interviews“.]