L.E.K. Consulting uses both experiential and case interviews, with the process varying by region and role. Prepare to explain your background and make a business recommendation from the information you're given; your invitation sets the actual rounds and timing.

This guide includes an original quantitative case you can attempt before reading the solution. It isn't an L.E.K. interview question, leaked material or an official scoring test.

Start with the firm's current guidance

L.E.K.'s application page describes a mix of experiential interviews and cases, including quantitative and strategic problems. Its case preparation page encourages candidates to clarify the question, organize an approach, use information and explain their conclusion.

The preparation page also supplies official example prompts. Work through those separately. Don't treat a candidate report about a written case or a particular office's round length as a universal rule. Check what your recruiting contact asks you to prepare.

For experiential practice, pick a real occasion when new evidence changed your decision. Explain your original reasoning, what you learned and what you did next. That also helps you practise the habit used in a case: revise a conclusion when its assumptions stop holding.

Original case: a warehouse sensor service

A sensor provider is considering a subscription service for independent warehouses in one region. The client wants to know whether the service could cover its incremental annual operating costs at the proposed price. Use the fictional inputs below. They aren't market data or facts about L.E.K.'s clients.

Start by clarifying the decision. Does the client want annual operating break-even, first-year cash recovery or a longer-term investment return? For this exercise, assess operating break-even first. Check the separate launch cost afterward.

Exhibit 1: customers and annual economics

Input	Fictional value
Warehouses in the region	400
Share meeting the installation requirements	50%
Share of that compatible group with the relevant monitoring need	60%
First-year customer win assumption	20% of eligible warehouses
Price per warehouse	£400 per month
Variable support and equipment cost	£150 per customer per month
Incremental fixed operating cost	£80,000 per year
Separate one-time launch expenditure	£25,000

Assume every customer starts on the first day and stays for all 12 months. Costs are limited to those listed. There is no ramp-up, churn or working-capital change in this simplified exercise.

Before reading further, estimate the eligible customer pool, annual revenue and contribution after variable costs. Then decide whether the proposed first-year customer count covers fixed costs. Show the units in each calculation.

Work the numbers before recommending a launch

The compatible pool is 400 × 50% = 200 warehouses. Of those, 200 × 60% = 120 have the relevant need. This is a filtered customer pool; it isn't your customer's first-year sales.

At a 20% win assumption, the provider gets 120 × 20% = 24 customers. Annual revenue is 24 × £400 × 12 = £115,200. Annual variable cost is 24 × £150 × 12 = £43,200.

Contribution after variable costs is £115,200 − £43,200 = £72,000. Subtracting £80,000 of fixed operating costs gives an £8,000 annual operating shortfall. Including the separate £25,000 launch expenditure gives a £33,000 first-year cash shortfall under the stated assumptions. Don't call revenue profit.

Each full-year customer contributes (£400 − £150) × 12 = £3,000. Operating break-even therefore requires £80,000 ÷ £3,000 = 26.67 customers. Round up to 27 full-year customers, because a fraction of a contract doesn't cover the cost.

Covering the launch expenditure as well would require £105,000 ÷ £3,000 = 35 customers. That's a different target from operating break-even.

Update the recommendation after new evidence

Now the client tells you its sales team can sign at most 30 full-year customers at £400 per month. Treat this as a new constraint in the fictional case, rather than proof those customers will sign.

At 30 customers, annual contribution is £90,000 and operating surplus is £10,000. After launch expenditure, first-year cash is still £15,000 short. The service could cover annual operating costs at that volume, but it wouldn't recover the launch spend in the first year.

Next test a price cut to £350 while holding the £150 variable cost unchanged. Contribution per full-year customer falls to (£350 − £150) × 12 = £2,400. Operating break-even rises to £80,000 ÷ £2,400 = 33.33, or 34 customers, above the stated capacity of 30.

At 30 customers and the lower price, contribution is £72,000, leaving the same £8,000 operating shortfall as the original 24-customer base case. A lower price is not automatically a better launch plan.

Give a recommendation with a condition

A defensible response is to investigate a limited pilot before committing to the full launch. State what the evidence shows: the base case misses operating break-even, while the capacity case clears it only at the original price. The launch expenditure remains unrecovered in year one at 30 customers.

Then name the unresolved decision. Are 27 or more full-year contracts credible at £400? Can the provider deliver support within £150 per customer? Would a pilot have a different cost structure? You haven't been given those answers, so don't invent a profitable pilot.

To test your explanation, ask a practice partner to reveal one change after your first recommendation: customers join halfway through the year. Recalculate the contribution for six months while keeping the annual fixed cost unchanged. Explain why contract count and annual customer-equivalents are now different.

Turn one mistake into your next practice task

Review your attempt before choosing another case. If you multiplied the win rate by all 400 warehouses, redo the customer filtering. If you stopped at £115,200, separate revenue from contribution. If you rounded break-even down, check whether 26 contracts actually cover £80,000.

For conversational rehearsal, use Soreno's AI Case Interviewer to attempt a case available in the app and explain your recommendation aloud. It can ask follow-ups and provides feedback after successful processing. Eligible trial practice is limited; continuing access requires a paid subscription. This article doesn't promise a preloaded L.E.K. case or the firm's official assessment.

Choose one correction from the feedback, verify its arithmetic yourself, and test it on a different case. Your next attempt should show whether you can make the decision from new inputs rather than recall this solution.