Dimensionamiento del aprovisionamiento de agua para el Maratón de París
Estime el número total de litros de agua consumidos por los corredores durante el Maratón de París.
This is a market sizing case in the format of the interviews run at McKinsey. Allow 25 min to work through its 4 steps, at an intermediate level. It mainly trains business sense, chart reading, calculation and structuring. Below you will find the brief and the questions of each step, without the answers: the point is for you to solve it yourself.
Skills practiced
- Business sense
- Chart reading
- Calculation
- Structuring
The brief
The client's question
El cliente le solicita que estime el número total de litros de agua consumidos por los corredores durante el Maratón de París.
4 steps to solve this case
Here are the questions you'll need to answer.
Solve each step with the AI coach that guides and evaluates you in real time.
How to approach this case
A market sizing is solved by stating your formula before writing down a single number. Pick a starting point you can estimate (a population, an installed base, a number of outlets), split it into segments that behave differently, then apply a frequency and a price to each. Say your assumptions out loud and round to keep the arithmetic simple. The interviewer grades the reasoning and the final sanity check of the order of magnitude far more than the result itself.
This case involves calculations: talk through your arithmetic out loud, round when it is reasonable and state the order of magnitude you expect before the exact result. It also includes a chart or table to read: first say what the axes show, then give the main message in one sentence before going into detail.
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Frequently asked questions
How long does this case take?▼
Allow 25 min to solve it under interview conditions. It is split into 4 steps, which you can also work on one at a time if you prefer to take it slowly.
What level is this case?▼
This case is rated intermediate. It assumes you can already structure a problem and carry a calculation without losing the thread, and it asks you to move from step to step without being guided at every question.
How can I practise this case?▼
On FrameLab, you can solve it in writing with the AI correcting each step, take it out loud with an AI interviewer leading the interview, or run it with a partner. The first 7 days are free.