McKinsey Red Rock Practice Study
Should Calderas Mining switch its haul fleet?
You are supporting Calderas Mining, an open-pit operator evaluating a switch from diesel haul trucks to an electric fleet. Read the briefing and both exhibits, save the facts that matter to your research journal, then compute the answer the client asked for.
- Two exhibits: fleet economics and haul volumes
- A research journal to separate signal from noise
- One calculated answer, checked against a tolerance
Investigation + one calculation · the 10-minute advisory timer starts when you begin
Candidates report Red Rock as a multi-phase case study with exhibits, a built-in calculator, and numerical plus written outputs. McKinsey has not published a detailed official breakdown, and details vary by cycle. This practice study mirrors the reasoning, not the live content.
Road to Offer is independent and not affiliated with or endorsed by McKinsey. This is original practice content built from publicly available information about the assessment format, not a copy of the live assessment. Formats change between offices and recruiting cycles.
New to Redrock? Read the McKinsey Redrock Study guide and the full McKinsey Solve guide.
The quick version: Red Rock is the McKinsey Solve case study module. Candidates report roughly 35 minutes across sequential phases, interpreting exhibits, calculating with a built-in calculator, and submitting numerical and written outputs. McKinsey has not published a detailed official breakdown, and details vary by cycle.
The trap in Red Rock is never the arithmetic
The calculation in a Red Rock phase is usually something a competent candidate could do untimed without error. What breaks people is everything around it: a unit line buried in an exhibit footnote, a fixed cost that does not scale with volume, a journal full of true facts that have nothing to do with the question. The assessment is testing whether you read carefully under time pressure and whether you notice which information actually changes the answer. That is the same skill that separates a clean case interview from one where the candidate confidently computes the wrong thing.
How the study works
You get the client objective, a briefing, and two exhibits: a cost comparison table and a volume chart. The research journal lists six facts, three of which change the calculation and three of which are context. Save the ones you think matter. The calculator handles the arithmetic so you are testing your reasoning rather than your mental math. Then enter one number in the stated unit. Coaching walks through the full solution and names the three errors that account for most misses. An advisory ten-minute countdown runs without ever locking you out.
View worked examples →
3 worked
The three Red Rock reading traps
Fair warning: these walk through the same three traps the study above tests, so play it first if you want an honest read.
- Example 1
An exhibit reports volumes in kilotonnes. The cost figures are per tonne. What happens if you miss the footnote?
ApproachReconcile units before computing anything. When an exhibit's unit differs from the rate's unit, convert explicitly and write the converted figure down rather than holding it in your head.
AnswerYour answer is wrong by a factor of a thousand and looks plausible.
- Example 2
Switching suppliers saves a fixed amount per unit but adds a fixed annual lease. Does the lease affect annual profit?
ApproachFixed costs still hit profit; they just do not scale. Compute the variable saving across total volume, then subtract the fixed charge once.
AnswerYes. Gross saving minus the fixed charge is the answer the client asked for.
- Example 3
The question asks for an answer in thousands of dollars and you computed 3,460,000.
ApproachRead the requested unit last, before you submit, and convert. Assessments that state a unit mark on it.
AnswerEnter 3,460. This study accepts the dollar figure too; the live assessment marks on the unit it states.
View common mistakes →
4 pitfalls
Four ways candidates lose a Red Rock phase
- Computing before reading the exhibit footnotesFootnotes carry units, scope, and exclusions. Read every one before touching the calculator; it costs fifteen seconds and prevents the most expensive class of error.
- Treating every true fact as a relevant factAsk what changes the number. Employee headcount and unrelated industry trends are usually true, provided deliberately, and irrelevant.
- Forgetting fixed costs because they are not per-unitSeparate variable from fixed explicitly, compute the variable effect across volume, then apply the fixed item once.
- Ignoring the requested unitRe-read the answer field label before submitting. Dollars, thousands, and millions are all common, and the live assessment does not convert for you.
How to solve Redrock-style study questions
Use this order: objective, evidence, relationship, calculation, implication. The same disciplined setup that structure drills build for frameworks applies to a data study.
- Restate the objective. Know the exact quantity or decision the study needs before opening every data point.
- Label relevant evidence. A true fact can still be irrelevant. Save facts because they enter the answer, not because they look important.
- Write the relationship. For example, total impact may equal population multiplied by rate. Writing the relationship exposes missing inputs before the calculator does, and keeping a short menu of consulting math formulas in mind makes this step faster.
- Calculate without dropping units. Keep percentage versus decimal, thousands versus units, and period definitions visible.
- Check the answer against the question. A correct calculation can still answer the wrong comparison.
Which Redrock math to practice
You do not need advanced mathematics. You need reliable setup, clean units, and enough pacing discipline to avoid spending several minutes rescuing one avoidable mistake. Timed case interview math practice and short math drills build that reliability.
A seven-day Redrock preparation plan
Spread the number work across mental math for case interviews and quick case interview math tips so each day targets a different weakness.
McKinsey says Solve is a gamified assessment of problem-solving ability and that performance is considered with the rest of the application. Its official guidance also prohibits recording, screenshots, outside tools, and assistance during the live assessment. Practice beforehand; do the real assessment alone.
How to review a wrong Redrock answer
Trace the error backwards instead of repeating the final calculation. Start with the submitted unit, then inspect the equation, the evidence saved to the journal, and finally the original objective. This reverse order finds the first broken link quickly.
A good debrief ends with one changed behavior. "Be more careful" is not observable. "Write the denominator beside every percentage before calculating" is.
Where Redrock fits in Solve
The complete Redrock Study guide covers reported format details and more worked math. The McKinsey Solve guide explains how Redrock, Sea Wolf, and SFL fit together — if your invitation includes those tasks, their free practice simulations cover the same way.
McKinsey and Solve are trademarks of McKinsey & Company. Road to Offer is independent and is not endorsed by McKinsey.
McKinsey Red Rock questions
What is the Red Rock study in McKinsey Solve?
Red Rock is the case study module of McKinsey Solve. Candidates report roughly 35 minutes working through sequential phases, interpreting data exhibits, performing calculations with a built-in calculator, and submitting numerical answers plus a structured recommendation. McKinsey has not published a detailed official breakdown, so phase counts and timing should be treated as candidate-reported and cycle-dependent.
Is this simulation the real Red Rock case?
No. The client, exhibits, journal facts, and figures are original Road to Offer content. McKinsey prohibits recording the live assessment. This study practices the reading and calculation discipline Red Rock rewards using our own scenario.
Is the calculator like the real one?
It performs the same job: arithmetic on screen so you are not tested on mental math. The live assessment's calculator interface differs and may change between cycles.
Is the research journal scored?
Not in this demo, which scores the single numerical answer. The journal is a real interaction with real distractors because deciding what matters is a genuine part of the module, and the coaching tells you which facts changed the calculation.
What should I practice after this?
Case math drills. Exhibit interpretation plus clean arithmetic under a clock is the exact overlap between Red Rock and live case interviews, and drills grade every rep.
Exhibit reading and case math, graded
Case math drills grade the same reading-then-calculating loop this study tests.