McKinsey Solve 2025: Redrock Deep Dive

This article is a deep-dive into the Ecosystem mini-game of the McKinsey Solve. All insights are updated for the 2025 version.

Please read the main article on the McKinsey Solve (2025 edition) if you haven’t done so.

Table of Contents

Overview of McKinsey Solve: Redrock

Redrock test interface

Redrock test flow

Redrock question types

Math in the Redrock test

Charts in the Redrock test

Redrock test tips

Practice with mock tests

Overview of McKinsey Solve: Redrock

2nd game in McKinsey Solve

In the 2025 version of the McKinsey Solve test, Redrock is the 2nd mini-game that the candidate has to take. It has remained in this position ever since the 2023 version of the test, when it was first deployed to replace the then-staple Plant Defense game.

Redrock is a math-and-charts test, not a game

In Redrock, you are placed into the role of a researcher on Redrock island. You will be given a research objective, and to fulfill it, you must go through a dozen math-and-charts exercises. (For this reason, we tend to refer to Redrock as a “test”, not a “game”, like Ecosystem and Seawolf).

The outward appearance of the Redrock test is much like a somewhat-gamified version of numerical reasoning tests you would take at other companies; what sets it apart is the incorporation of a research journal and a calculator on the interface, which presumably is to help McKinsey figure out the candidate’s thought process better than previous games/tests.

In Redrock, no business, accounting or finance knowledge is required. All known Redrock tests take place in pseudo-biology settings (that is, it takes the theme of preserving animals and wildlife, but it’s not actual biology).

Time limit is 30 minutes

The time limit allocated to the Redrock test is 30 minutes, flexibly allocated between tasks (i.e. if you finish early tasks soon, you will have more time for later tasks). All tutorials are untimed.

As there are more than a dozen questions in Redrock (we assume a 14-question average), this results in a 2.1 minute per question average. This limit is about “just enough” for most candidates. Well-prepared candidates can go through this task in about 20-25 minutes.

Redrock test interface

Collectible data

On the Redrock test interface, the centre is reserved for the exercises and their related data (text, tables, charts, etc.). Some of the data would look like buttons: these are collectible data, meaning they can be dragged and dropped into answer boxes, the calculator, the journal, etc.

Collectible data are mostly, but not always, numbers. All data necessary to solve Redrock exercises will be collectible (but not all collectible data will be necessary).

Research Journal

The right hand side of the screen is reserved for the Research Journal, which is a deposit for collectible data, i.e. you can (and must) place collectible data here at the start of the test, so they can be used to solve later exercises.

Once placed on the Journal, each collected data piece will appear as a card, with its own title and description. You can change the positions of already-collected data, or change the title of each piece of data so it’s easier to work with them later.

On-screen calculator

The calculator in Redrock appears whenever you need to solve math exercises. It is a simplified version of the hand-held calculator. It lacks a few features compared to normal calculators (such as powers), but it has every feature that the Redrock test needs.

Most importantly, it logs every single answer (instead of just one last answer like most calculators do), and all answers are logged as collectible data without rounding, so you can drag them onto answer boxes, or the journal, or reuse them for later calculations.

Redrock test flow

Two parts: Study and Cases

Each Redrock test is divided into two parts: Study and Cases. Study is in turn divided into 3 phases: Investigation, Analysis, and Report, while Cases are divided into 6 cases. Between each part and phases, there will be interactive and untimed tutorials.

All of these parts and phases are displayed on the left side of the screen.

Study - Investigation, Analysis, Report

The first part (Study) is divided into Investigation, Analysis, and Report:

In Investigation, you will review about an A4-page worth of data, including: a research objective, a few paragraphs of text, along with 2-3 tables and charts, and some clues to help them figure out the math formulas needed to reach the objective. In this part, only the Research Journal is available, not the Calculator.
Next, in Analysis, you will solve 2-4 math questions (usually 3), using the data collected in Investigation. Here the Calculator will be available for the first time. When each question is solved, the answers will be collected automatically into the Journal.
Finally, in Report, you will use the answers from Analysis to finish a report, including: a few paragraphs, choosing a chart type, and filling in a table. Here you can no longer return to Analysis and Investigation, so it’s important to collect all necessary data beforehand.

Throughout Investigation, all the tasks and questions are interdependent, i.e. if you get your answers wrong early on, it will cascade and cause even more wrong answers.

The Study often follows the theme of preserving wildlife on the Redrock island, so no business knowledge is necessary.

Cases (6 cases total)

The second part (Cases) contain 6 cases.

The cases follow the same theme as the Study, as if belonging to one storyline.
However, the cases are independent from the Study part, and from each other (i.e., if you make one mistake, it will not cascade and cause other mistakes down the line).
The question types will be mostly the same as the Study; the Calculator is almost always present, and the Journal sometimes appears.

Once the Cases part is done, the Redrock test is finished and you will move on to the next test / mini-game, which is now Seawolf.

Redrock question types

Math (calculation, formula)

Math questions take up about 60-70% of all Redrock test questions. They can be divided into two subtypes: calculation and formula.

Calculation questions require you to reach answers. They either come in multiple-choice format where you select a correct answer / option, or in the fill-in-the-blanks format, with the latter being much more common.
Formula questions require you only to reach the formula, as the name suggests. They come in two formats as well: either multiple-choice, or “drag the necessary numbers into the journal” (which require you to figure out the formula first).

The Calculator is present in all calculation questions (obviously!), but not in formula questions because there you don’t need to reach the answer.

Reading (text, chart)

Reading questions takes up about 20% of all Redrock test questions. They involve reading text and/or charts and/or tables, then choosing correct options or filling in blanks.

The biggest of all these “reading” questions is actually the Investigation phase of the Study. Then there is usually one reading question in the Cases as well.

Reading questions usually involve dealing with large amounts of data: about 200-400 words of text, and/or charts and tables with a few dozen data points. They might also require you to understand statistics terms, mostly mean, mode and median.

The charts used in reading questions are relatively simple ones: the classic line, pie and bar charts, their stacked variants, scatter plots, tree maps, etc.

Visualization (chart)

Visualization questions in Redrock require you to choose an appropriate chart type to illustrate a set of data. They take up the remaining 20% of Redrock questions. The format is usually multiple-choice, or fill-in-the-blanks.

Sometimes the data set is given, like in the Report phase of Investigation, sometimes the data set is described using plain text (e.g.: the question text might say “customer responses in a survey” without showing the actual responses).

The chart types involved in visualization questions are the same as in reading questions. Sometimes they allow you to see the type of chart, either through a thumbnail or an interactive chart, sometimes they just list the names of the chart types.

Math in the Redrock test

Basic operations (+, -, *, /)

Most of the calculations in Redrock will revolve around basic operations (addition, multiplication, subtraction, division), for the simple reason that these form the basis of real-world analysis.

For example, you will need to calculate the change in the number of lions from this year to that year, the total population of lion packs meeting certain criteria, etc.

The calculations are made more difficult by “chaining” them together, i.e. having the candidate perform 3-4 consecutive operations to reach one answer, and/or use that answer to feed into another question. That is, the individual operations are not difficult, but you have to perform them in the correct order, and do so correctly every single time.

Percentages

Percentage calculations are a staple of the Redrock test.

For percentages, it’s important to differentiate between “percent” and “percentage points”. Both are present in Redrock, and McKinsey makes no effort to explain them in the instructions so it’s likely that they expect you to know the difference.

Here’s an example:

If lion pack A is 60 percent the population of lion pack B, and lion pack C’s population is 20 percent higher than lion pack A, then lion pack C’s population is 60 percent * (100 + 20 percent) = 72 percent the population of lion pack B.
If lion pack A is 60 percent the population of lion pack B, and lion pack C’s population is 20 percentage points higher than lion pack A, then lion pack C’s population is 60 percent + 20 percent = 80 percent the population of lion pack B.

These percent / percentage point calculations are very common in Redrock, with about one third of the questions involving measuring percentage changes or percentage gaps.

Averages

For averages calculations, it is important to know the differences between mean, mode and median, as well as how to calculate “weighted averages”.

We’ll go through the trio of mean, mode and median first:

Mean: this is the “normal” average. You simply sum up all the values, then divide that sum by the number of values.
Median: this is the middle value in a data set, when the values are ordered (if there are an even number of values, the median is the mean of the two middle values).
Mode: this is the most frequent value in a data set

For example, given the data set: {2, 4, 4, 4, 5, 6, 10, 15, 16}

Mean = 7.33
Median = 6
Mode = 4

Next, we’ll deal with “weighted average”. In a set of values meant for weighted average calculation, each value comes with a “weight”. To calculate the weighted average, we must multiply each value with its weight, then add the results together, then divide that sum by the sum of all weights.

For example, given the following values {5, 6, 7, 8} and their weights {0.5, 0.2, 0.2, 0.1}, the “normal” average would be 6.5, while the weighted average would be (5*0.5 + 6*0.2 + 7*0.2 + 78*0.1) / (0.5 + 0.2 + 0.2 + 0.1) = 5.9.

Basic probabilities

Probability calculations in Redrock tend to be relatively simple. For example:

“Suppose we have 2 crates of balls. Inside each crate, there are 10 balls painted with 5 colors (red, blue, green, yellow, purple), each ball having only 1 color, and there are 2 balls for each color. Suppose we pick 1 ball out of each crate, what is the percentage chance that they are both red?”

(the answer to this question is 20% x 20% = 4%).

If you want to know more about probabilities (supposedly for future proofing), these are the terms you need to familiarize yourself with:

Independent vs dependent events: If event B depends on event A, then event A happening will change the probability of event B happening (in the above example, the picking of one ball from each crate are independent events, because the two crates are separate).
Mutually exclusive vs non-mutually-exclusive events: Event A happening will ensure that event B cannot happen (in the above example, the colors of the balls in each crate are mutually exclusive - each ball can only be of one color).
Complementary events: these events are MECE, if we are to use consulting terms (in the above example, a ball can only be either red, or not-red, so we say that these are complementary events, or in consulting language, MECE).

Charts in the Redrock test

Simple charts: bar, line, pie

Let’s get straight to the point and discuss how these charts are used. Learning these charts alone will likely get you through half the chart-related questions in Redrock:

The bar chart is used to compare independent values, usually in the same time frame. Alternatively it can be used to visualize change over time but only with a small number of intervals. Examples: population of 5 packs of lions, or population of a lion pack across 5 years.
The line chart is used to almost exclusively visualize change-over-time, and it is especially effective if the data involves a large number of intervals. For example: food consumption of a lion pack every week, across 5 years (260 intervals).
The pie chart is used to visualize how much each part takes up a larger whole. For example, the contribution of population from each lion pack to the total number of lions in a park.

Stacked charts: stacked area, stacked bar

The stacked area and stacked bar charts are hybrids of the bar, line and pie charts:

The stacked area chart is the combination of a line chart and a pie chart, it is used to visualize changes in composition as well as changes over. It has a “100%” which solely focuses on changes in composition.
The stacked bar chart is the combination of the bar chart and the pie chart, it is used to visualize the compositions of independent “wholes” as well as comparing the total numbers. It also has a “100%” which solely focuses on composition.

Other charts: radio, scatter plot, etc.

These “less common” charts in Redrock tests include:

The scatter plot: used to display relationship between two variables
The bubble chart: a scatter plot variant, where dots are replaced by bubbles of varying sizes to display a third variable.
The tree map: a rectangular variant of the pie chart
The radar chart: comparing attributes of one item
The histogram: a bar chart with many bars and no gap between them, often used to display distribution / frequency of values in a data set.

Redrock test tips

Use the on-screen journal & calculator

Technically speaking, you can finish the entire Redrock test without ever touching the Research Journal and the Calculator, EXCEPT when the test requires you to use them (say, in Investigation or in case questions about collecting data).

You can note down the objectives on a piece of paper, and use a hand-held calculator, or you can use an Excel sheet. They can be as fast and as accurate.

However, we recommend you always stick to the on-screen tools, for two reasons:

McKinsey likely tracks your behavior on these tools, so making your behavior less transparent to them might affect your scores.
These on-screen tools preserve your numbers in their un-rounded form, preventing accumulating margins of error that result from roundings.

Use a numpad keyboard

A problem with using these on-screen tools is that they are quite clunky, because you need to move data with your mouse, type in numbers by clicking on a virtual keyboard, etc.

However, you can make it somewhat faster if you use a numpad. The calculator receives input from your physical keyboard, so using it will be faster (in fact, it can shave off a few minutes of your test time).