Case Interview Maths McKinsey

Question

Hi everyone,

I thought it can be a good idea to create a list for the quantitative part of the case at McKinsey (all maths possibility questions). Please feel free to add more to the list

1) ask you to calculate cost savings

2) ask you to calculate the gross margin

3) ask you to calculate the price point to break even

4) ask you to calculate how many units must be sold to breakeven

5) ROI

6) how to achieve a specific amount of ROI

7) payback period

8) ask you to calculate the market share whilst only providing population, market share of another country, and the 1% of market share of that country

9) ask you to calculate the output ? (not sure)

10) market sizing

11) CAGR? or calculate x using CAGR numbers (not sure)

12) should we expect NPV calculation??

Answer 1

Hey there,

I agree with Ian here.

Its a noble effort but it won't get you very far for two reasons:

You will never be able to collect all the possible math problems there are.
Even if, let's say your case includes a breakeven calculation, it could be asked in a way that is not entirely clear from the start what you need to do and there might be different potential approaches that could work. Interviewers won't ask ‘’can you calculate the break-even here'' but they will package it into a more obscure question in the context of the case that you need to figure out how to approach.

As a result, trying to anticipate what kind of case you will get (industry, function, problem) or what math problem you could potentially get only sets you up for failure as for McKinsey it's all about how you approach a problem. That is also why a cookie-cutter approach usually does not work.

I have seen it many times over that people who focus on the what rather than the how to get into this spiral:

False sense of security > go to the interviews > it does not go their way since they expected something different > try to fit something into the answer that does not fit / overlook a much simpler or more elegant way to approach the problem > panic > rejection.

Rather focus on working on your core math and quantitative reasoning skills. This will build a holistic understanding of the logic, which is the foundation to solving every quant problem.

Cheers,
Florian

Answer 2

Hi there,

It's definitely good to have a list and this is a good start!

That said, even if you had a list of 1,000 you wouldn't be completely covered! Definitely practice and build up your repertoire, but also remember this is less about memorization and more about learning how to think through problems! Make sure you know how to break down whatever math problem comes your way.