Case interview examples, with full solutions

Each has its own page: the prompt, the facts the interviewer gives, every exhibit, a step by step walkthrough, the math, a model answer and the common mistakes.

1. Profitability

   Ridgeway Cold Storage

   Profit fell from $24M to $15M on flat revenue. Find why and what to do.

   Read the full solution

2. Market sizing

   Tundrix Cooling

   How much liquid cooling will new AI data centers need next year?

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3. M&A

   Halvern Machinery

   Should a machinery maker buy its sensor supplier for $200M?

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4. Market entry

   Vestiura

   Should a fashion brand launch a clothing rental subscription?

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5. Pricing

   Prairiestead Seeds

   A value-based price for a seed that pays off only in drought years.

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6. Private equity

   Tidewater Freight

   Should a fund buy an asset-light freight broker at $450M?

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7. Product strategy

   Grocery delivery

   Should a restaurant delivery app expand into grocery?

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8. Growth strategy

   CruiseQuest

   Would a private island pay off for a cruise line?

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Copperleaf Grill runs 30 casual dining restaurants. Revenue has held at $90 million a year for two years, but operating profit fell from $12 million to $6.6 million. Why, and what should it do?

1. Structure

   Revenue first, then each cost

   Split profit into guests times the average check on one side and food, labor and rent on the other. Revenue is flat, so ask whether its two parts moved, then find the cost that grew.

2. Data

   What you get when you ask

   Guests rose from 3 million to 3.6 million a year after a weekday discount menu launched, and the average check fell from $30 to $25. Food costs about $9 a guest. Labor stayed at $30 million and rent and other costs at $21 million.

3. Math

   Food costs rose $5.4 million

   Food went from 3 million × $9 = $27 million to 3.6 million × $9 = $32.4 million, which is the whole profit drop. Per guest, the check minus food fell from $21 to $16. The 600,000 new guests add $9.6 million, but the 3 million guests Copperleaf already had each bring $5 less, $15 million in all.

4. Recommend

   Pull the discount back

   “Profit fell $5.4 million because the discount menu cut the average check from $30 to $25 while food still costs $9 a guest. The extra 600,000 guests don't make up for $5 less from the 3 million we already had. I'd keep the discount only in the slowest weekday hours and test that in a few restaurants. The risk is losing the new guests, so I'd track how many come back at full price.”

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Quillbrook Coffee runs 200 cafés in the US and is thinking about opening 25 in Mexico City. It wants each new café to earn back its build cost within 3 years. Should it go ahead?

1. Structure

   Four questions, one decides

   Is the market attractive, who already serves it, can Quillbrook win there, and does one café pay back in time? The last one decides the yes or no, so size one café first.

2. Data

   One café's numbers

   A café costs $500,000 to build. Quillbrook expects 400 customers a day at an average ticket of $4, open 360 days a year, and a 20% operating margin before head office costs.

3. Math

   Payback of about 4.3 years

   Revenue is 400 × $4 × 360 = $576,000 a year, and 20% of that is $115,200. Payback is $500,000 ÷ $115,200, about 4.3 years. To pay back in 3 years a café needs $166,667 a year, which at a 20% margin is $833,333 of sales, about 580 customers a day.

4. Recommend

   Not as planned

   “Not as planned. At 400 customers a day a café pays back in about 4.3 years, over the 3-year bar. It would need about 580 customers a day, or a build cost near $346,000. I'd open three to five smaller cafés first to test real traffic, and talk to a local partner who already holds good sites.”

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Dunmore Snacks, a US snack maker, can buy Orchardine, a maker of fruit bars, for $300 million. Dunmore pays no more than 12 times operating profit for a snack business. Should it buy?

1. Structure

   Value alone, value together, price

   What Orchardine earns on its own, what the two companies could add together, and whether the price leaves any of that for Dunmore. Then the risks that could break the deal.

2. Data

   The target and the synergies

   Orchardine sells $150 million a year at a 12% operating margin. Dunmore's sales force could lift Orchardine's sales 20% at the same margin, and buying ingredients together would save $4.4 million a year.

3. Math

   16.7 times today's profit

   On its own Orchardine makes 12% × $150 million = $18 million, so $300 million is about 16.7 times profit. The sales lift adds $30 million × 12% = $3.6 million, and with the $4.4 million of savings, profit reaches $26 million, about 11.5 times. At 12 times, Orchardine alone is worth $216 million, so Dunmore would pay $84 million for synergies, $7 million a year of the $8 million it expects.

4. Recommend

   Buy, at a lower price

   “Buy, but bring the price down. $300 million is 16.7 times what Orchardine earns today, and it only fits Dunmore's 12-times rule if $7 million of the $8 million a year in synergies shows up. I'd offer less or tie part of the price to the sales lift. The biggest risk is that lift, since shared buying is easier to lock in.”

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Tallybook sells bookkeeping software to 20,000 small businesses. It is adding payroll as a paid add-on. What should it charge each month?

1. Structure

   Cost, alternatives, value

   Three anchors: what payroll costs Tallybook to run, what customers pay for it elsewhere, and what it is worth to them. Then pick the price that earns the most over cost, given how many customers will buy.

2. Data

   Cost, rival price, survey

   Payroll costs Tallybook $8 per customer a month. The average customer has 6 employees and would pay a standalone payroll tool $45 a month plus $5 per employee. A customer survey says 25% would add payroll at $59 a month and 15% at $75.

3. Math

   $59 earns more than $75

   Elsewhere the average customer pays $45 + 6 × $5 = $75. At $59, 5,000 customers each earn $51 over cost: 5,000 × $51 × 12 = $3.06 million a year. At $75, 3,000 customers earn $67 each, $2.41 million. $59 stays ahead as long as about 3,940 customers, 20%, sign up.

4. Recommend

   Charge $59 a month

   “Charge $59 a month. It sits under the $75 the average customer pays for a standalone tool, and at the survey's 25% take-up it earns about $3.1 million a year over cost, against $2.4 million at $75. Surveys overstate buying, so I'd launch to a slice of customers first and check that at least 20% sign up.”

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A startup wants to clean windows for homeowners. How big is the yearly US market for home window cleaning?

1. Structure

   Top down from households

   Households, the share living in houses, the share of those paying someone to clean their windows, how often and at what price. Say the formula before any numbers.

2. Assumptions

   Round numbers, said out loud

   Assume about 130 million US households, 65% of them in houses, 10% of those paying for window cleaning, 2 times a year at $250 a visit. These are your assumptions, so say why each is reasonable.

3. Math

   About $4.2 billion a year

   130 million × 65% = 84.5 million houses. 10% of those is 8.45 million paying households. 8.45 million × 2 × $250 = about $4.2 billion a year. That is $500 a year per paying household, which is a sensible check for a service bought twice a year.

4. Answer

   About $4 billion, and what moves it

   “About $4 billion a year. The number that moves it most is the 10% who pay: at 5% the market halves to about $2.1 billion. Before the startup commits, I'd test that share with a quick survey in its first city.”

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Cragline runs 12 climbing gyms. The owners want $3 million a year more operating profit within three years. Should it open new gyms, add youth programs to the gyms it has, or both?

1. Structure

   Compare the two bets

   Profit added, upfront cost and how fast each pays back. Then check whether either one alone reaches the $3 million goal.

2. Data

   Gyms and programs

   A new gym costs $2.5 million to build and earns $600,000 a year once it fills up, after about two years. A youth program costs $50,000 per gym to set up and signs up 150 children at $120 a month, with a 40% margin.

3. Math

   About $3.4 million together

   Per gym, a youth program brings 150 × $120 × 12 = $216,000 of sales and 40% of that, $86,400, in profit. Across 12 gyms that is about $1.04 million a year for $600,000, paid back in about 7 months. 4 new gyms add 4 × $600,000 = $2.4 million a year for $10 million, about 4.2 years to pay back.

4. Recommend

   Both, programs first

   “Do both, youth programs first. They add about $1 million a year and pay back in about 7 months. 4 new gyms add $2.4 million more, which takes the total to about $3.4 million, above the $3 million goal. The risk is a gym taking longer than two years to fill, which would miss the three-year goal, so I'd start building now in the areas where our gyms are busiest.”

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Pellwood Fulfillment's warehouse handles 20,000 orders a day, and 12% of them miss the same-day shipping cutoff. Each late order costs $8 in rush shipping. How should Pellwood fix it?

1. Structure

   Follow one order

   Receive, pick, pack, ship. Find the step with the lowest daily capacity, because that step sets how many orders leave on time.

2. Data

   Capacity at each step

   100 pickers each pick 25 orders an hour, and 40 packing stations each pack 55 orders an hour. Both run one 8-hour shift, 300 days a year. A new packing station costs $40,000 and its packer $45,000 a year.

3. Math

   Packing is the bottleneck

   Picking can do 100 × 25 × 8 = 20,000 orders a day, but packing only 40 × 55 × 8 = 17,600. The 2,400 orders packing can't reach are the 12% that miss. At $8 each that is $19,200 a day, about $5.8 million a year. 6 more stations raise packing to 46 × 55 × 8 = 20,240 a day.

4. Recommend

   Add 6 packing stations

   “Add 6 packing stations. Packing handles 17,600 orders a day against 20,000 picked, and the late orders cost about $5.8 million a year in rush shipping. 6 stations cost $240,000 upfront and $270,000 a year in staff. Once packing keeps up, picking runs at its full 20,000 a day, so I'd plan extra pickers before volume grows.”

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1. 1. Structure

   Cover the steps, say your split

   Two minutes per prompt, out loud, then open the worked steps and compare. Do all seven in one sitting to feel how the types differ.

2. 2. Free case

   Work a full sample case, no sign-up

   A full case with a timer and a worked answer. Each case type page has its own.

   Free sample caseProfitabilityMarket entry

3. 3. Math

   Get the arithmetic fast

   Payback, margins and percentages come up in almost every case above. Timed drills help, and they are free.

   Case math drillsMarket sizing builder

4. 4. Out loud

   Run a full case with an AI interviewer

   The 12 cases below are in Soreno's question bank under the same client names. The interviewer hands out data when you ask, shows exhibits and pushes back.

   AI case interview

Profit moved the wrong way.

1. 1

   SuburbRents owns 5,000 single-family rental homes. To lift margins the CEO raised rents 10%, from $2,000 a month to $2,200, a plan meant to add about $12 million of profit. Instead operating profit fell from $60 million to $57.5 million. What went wrong, and what rent increase should SuburbRents use at next year's renewals?

   SuburbRents · Real estate · Medium · Candidate-led

   Show how to start

   Rebuild the $12 million the plan expected first. Then lay out everything else that moves profit in a rental business and ask what changed. Try this case out loud

2. 2

   Northmere Kidney Care runs 150 outpatient dialysis clinics. Two years ago it made $150 million of operating profit, and this year it expects $80 million. Treatments haven't changed, and the CEO says the clinics cost about the same to run. Why has profit fallen so far, and how does Northmere get it back?

   Northmere Kidney Care · Healthcare · Medium · Interviewer-led

   Show how to start

   Build a profit tree for the clinics, then ask for data on each branch before you settle on a cause. Try this case out loud

A client weighs a market it has never served.

1. 3

   Marivelle Cruises runs large ocean ships in the Caribbean, where margins are thin. To reach wealthier travelers it is looking at luxury week-long river cruises in Southeast Asia, on ships it would build itself. It has never run river ships. Should it enter, and if so, what kind of ship should it build?

   Marivelle Cruises · Travel · Hard · Candidate-led

   Show how to start

   Two questions in one prompt. Agree on the order, then cover the market, Marivelle's ability to run a river ship and the economics of one ship. Try this case out loud

A deal, and whether it adds value.

1. 4

   Marquee Lane Cinemas, a chain of 200 theaters, plans to buy Immerso, a startup that runs virtual reality gaming lounges, for $30 million, then put a lounge in every lobby where the second concession stand is today. Will the acquisition and the rollout be profitable?

   Marquee Lane Cinemas · Media · Medium · Candidate-led

   Show how to start

   Two things to judge, the price and the rollout. Work out what one lounge would mean for one theater before you scale it across the chain. Try this case out loud

2. 5

   The government of Velmora owns the national bus operator, which runs city routes and rural routes to about 200 villages. An infrastructure fund offers $200 million in cash for the whole company. Over the next ten years, would the sale improve the government's finances, and if not, what should it do?

   Velmora State Buses · Public sector · Medium · Interviewer-led

   Show how to start

   Restate the goal as the government's finances, not the price, then ask what you need to know about the bus company today. Try this case out loud

A price or a payout needs a new design.

1. 6

   Ferrovane Lubricants sells specialty lubricants by the barrel at $100, with 15% off any order of 1,000 barrels or more. Revenue has grown, but contribution margin has shrunk, and the plant runs heavy overtime every fourth quarter while sitting half idle the rest of the year. Design a new pricing structure.

   Ferrovane Lubricants · Energy · Hard · Candidate-led

   Show how to start

   Say what a good structure should achieve, using the symptoms in the prompt, before you design one. Then ask for the data you need on customers and volumes. Try this case out loud

2. 7

   Clearwell Plasma pays donors $40 a visit. To steady its supply, the CEO wants to pay regular donors a flat $150 a month for coming at least twice, whether they come 2, 3 or 4 times. Its own medical policy allows at most 4 donations a month. Would this improve Clearwell's operating margins?

   Clearwell Plasma · Healthcare · Hard · Candidate-led

   Show how to start

   Write down what Clearwell earns and pays for one donation today, then build the plan's numbers next to it. Try this case out loud

An estimate that feeds a decision.

1. 8

   Tundrix Cooling makes immersion cooling systems for new data centers in its home region. Sales has set a target of 100 megawatts of cooling next year, described as just 5% of what new data centers will need. Estimate that need, how much Tundrix can realistically sell into, and whether the target holds up.

   Tundrix Cooling · Technology · Medium · Interviewer-led

   Show how to start

   Three parts in order: total demand, the share Tundrix can reach, then the target. Pick top down or bottom up for demand and say why. Try this case out loud

A growth plan to test before the client commits.

1. 9

   Corvane Pay processes payments for B2B wholesalers at a flat $0.50 a transaction and earns about $125 million a year. The CEO plans to switch every merchant to 1% of each transaction's value, which her team says could multiply revenue several times. Is this the right way to grow, and if not, what should Corvane do?

   Corvane Pay · Financial services · Medium · Interviewer-led

   Show how to start

   Check the team's claim before you build on it, and ask what you need to know about Corvane's merchants. Try this case out loud

2. 10

   Corvelle Beauty, a European makeup and skincare brand, has always sold through department store distributors. The board wants $200 million of sales in Southeast Asia, at consumer prices, within five years, and the plan copies the usual approach. Can that plan reach the goal, and if not, what should Corvelle do?

   Corvelle Beauty · Retail and consumer · Medium · Candidate-led

   Show how to start

   The goal is a number, so restate it and say how you would test whether the plan on the table can reach it. Try this case out loud

A process that can't keep up, or costs too much.

1. 11

   Kestrel Enclosures makes steel electrical cabinets that go through welding, painting and final assembly, in that order. Customers order about 650 a day, but the plant ships 500. The plant manager wants $2 million of fast-drying lamps to lift the paint shop from 500 to 700 cabinets a day. Should the COO approve it?

   Kestrel Enclosures · Industrial · Hard · Interviewer-led

   Show how to start

   Restate what the COO has to decide, then ask what you need to know about the plant before you judge the $2 million. Try this case out loud

2. 12

   The City of Wexbridge collects trash weekly from 50,000 homes. Its budget is $18 million a year, but costs have reached $20 million, mostly from diesel. The mayor wants pickups every other week with larger bins, saying half as many pickups will halve the fuel bill. Does the plan work, financially and operationally?

   City of Wexbridge · Public sector · Hard · Candidate-led

   Show how to start

   The mayor needs two answers, financial and operational. Ask for the city's cost lines before you work out any savings. Try this case out loud

• A blended number that hides the answer

  Averages across stores, gyms or customers can say no when one segment says yes. Ask how the parts differ before you add them up.

• A per-customer number where the total decides

  Tallybook's higher price earns more per customer and less in total. Carry every option through to total profit.

• A target taken as given

  Payback bars, multiples and growth goals are the yardstick. Restate the client's bar early and compare every number against it.

• A no with nothing after it

  Quillbrook's answer is no as planned, then what would make it yes. Give the client a way forward.