Solve, McKinsey’s assessment game

I'm preparing to McK coming next week
New answer on Jan 15, 2022
3 Answers
Anonymous A asked on Jan 14, 2022

Hi all, 


did anyone recently go through McKinseys pre-assessment game named “Solve”? 
Would be keen to get some perspective on 

  • What type of challenges to expect (maybe even concrete examples) 
  • How to best prepare for it (McK says no prep is needed but asking here nevertheless) 


Thanks in advance for your help! :) 

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Content Creator
replied on Jan 14, 2022
#1 rated McKinsey Case and PEI Coach | 5 years at McKinsey | Mentorship Approach | 120+ McK offers in 18 months

Hey there,

The Solve Game takes between 60 and 75 minutes.

There are two games you will have to play. All candidates I interviewed in the last 5 months reported the following:

1. Ecosystem creation

Build a food chain, consisting of 8 species and place it on a map. You will get a menu with a lot of different species (animals and plants) and have to read through a bunch of data points for each (+ there are videos on Youtube)

Some tips on how to proceed:

  • Start your food chain top-down with the predator first
  • Calculate that kcal produced in one layer of the food chain > kcal depleted by the layer above
  • On top of kcal, ensure that the food chain works from a conditional perspective (not every animal or top predator can eat every plant or other animal, etc.). I have heard often from candidates that optimize kcal and then neglect this factor, leading to a rejection
  • Make sure that all 8 animals in your chain can survive in the given location (check quickly for each variable)
  • Check if your food chain and location fit with any additional boundary conditions (e.g. additional rules you need to consider when building your food chain and matching it with a location) which have been implemented mid-last year to make sure candidates have a harder time preparing and some uncertainty of what to expect

Allocate 5 minutes at the end of the scenario before pressing submit to check for these 4 elements. If you can confirm all, you can be sure to have created a sustainable ecosystem.

2. Plant defense

You need to defend a plant species from invaders using several tools at your disposal in a static, round-based tower defense-style game. The tools consist of barriers that slow down invaders and predators that damage and eradicate them.

There are several rounds you will play with increasing complexity and stress levels as the maps become bigger and the invaders more numerous. Your goal is to have the plants survive each of these increasingly difficult rounds.

The game is static and turn-based in nature and not dynamic like many other tower defense games. Before each turn, you can devise or revise your strategy and select a number of animals and barriers to protect your plant.

A few general tips

  1. Prepare using Plants vs. Zombies, Kingdom Rush, and Tower Duel
  2. Move swiftly through the selection of your barriers and predators and use the symbiotic power of both (e.g. slow attackers down with a barrier and place your predators next to them slow-down --> it is a called a choke point in tower defense games)
  3. Be mindful of the attackers (how fast do they move, what is their path)
  4. Be mindful of the stats of your predators and barriers (how much damage do they inflict? how big is there is their sphere of influence? how much do they slow down the attackers?)
  5. Always think 2 steps ahead (about the route of the attackers and adjust your strategy as you see fit)

Source: I interviewed more than 320 test-takers from November 2019 onwards and constantly devise(d) new strategies to beat the game. 

If you book a coaching with me I am happy to share my 100+ page guide with strategies and 4 videos for each game + an Excel template for the first game.



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Content Creator
replied on Jan 15, 2022
#1 Coach for Sessions (4.000+) | 1.500+ 5-Star Reviews | Proven Success (➡ | Ex BCG | 9Y+ Coaching

Hi there,

1) What type of challenges to expect (maybe even concrete examples) 

You will have to solve two games. 

Since the launch of the Solve game (also called Imbellus or PSG), McKinsey has used 5 games:

  • Ecosystem Management
  • Plant Defense
  • Disaster Management
  • Disease Management
  • Migration Management

The most common are Ecosystem Management and Plant Defense. However, in the last year the candidates I coached got all the cases, with the exception of Disaster Management. 

Some games are more common in some geographies (please PM me for info).

2) How to best prepare for it (McK says no prep is needed but asking here nevertheless) 

You can check the following guides (full disclosure: I am the author;) )

The version with the video simulation includes:

  • 15 videos showing how to crack the Ecosystem Game in 23 minutes (instead of the recommended 35) and resist 25+ turns in the Plant Defense (instead of the minimum target of 15)
  • Automated Excel with Formulas to build a chain in 16 minutes
  • PDF guide with all the 5 games and how to crack each of them

If you have other questions please PM me, I will reply within 12 hours.



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Content Creator
replied on Jan 15, 2022
MBB | 100% personal interview success rate (8/8) and 95% candidate success rate | Personalized interview prep

Hi there,

This is also known as the Imbellus test and you should absolutely prep beforehand!

What type of challenges to expect (maybe even concrete examples)

The two most common are a tower defense game (with animals attacking your plant) and then an ecosystem building game (where you have to select the right animals in a food chain to ensure they survive). There are also 3 less common ones (Disease Management, Disaster Management, and Migration Management)

How to best prepare for it (McK says no prep is needed but asking here nevertheless)

I have a full prep plan I send to my candidates. This includes 3 videos I have recorded to walk you through, step by step, the Tower Dense and Ecosystem Games (articulating exactly what you need to do to solve them). Feel free to reach out for this!

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Content Creator
#1 rated McKinsey Case and PEI Coach | 5 years at McKinsey | Mentorship Approach | 120+ McK offers in 18 months
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