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4. Per order: an online grocer in Brazil

You run the case. Read the prompt, answer questions from the notes below, and share data only when the candidate asks for it or gets stuck. Score at the end.

Case timer

00:00

Target length:

1. Read the prompt aloud

Read it slowly, then pause. Let the candidate ask questions before they structure.

A fictional online grocer in São Paulo has an average order of BRL 120, with a gross margin of 22 percent on the groceries. For each order it pays BRL 6 to pick and pack, BRL 9 for delivery, and payment fees of 2 percent of the order. Each small warehouse (a dark store) costs BRL 90,000 a month to run. How many orders a day does a dark store need to break even?

2. Answers to clarifying questions

This case has no scripted clarifying answers. Answer from the prompt, and say "assume what you think is reasonable" if the prompt does not cover it.

3. A model structure

Compare the candidate's structure with this one. A different split can be just as good if it is clean and fits the problem.

Breakeven orders = dark store fixed costs / contribution per order
- Gross profit per order
- Minus picking, delivery and payment costs
- Orders per month and per day

4. The working, step by step

Each step shows how a strong candidate works it out. Share a new fact from it only when the candidate asks or is stuck, and let them do the math: the result in the dark box is what they should reach.

Step 1: Gross profit per order
What a strong candidate does: BRL 120 at a 22 percent margin.
Gross profit per order (BRL): 120 × 0.22 = 26.4
Step 2: Payment fee
What a strong candidate does: 2 percent of the order.
Payment fee per order (BRL): 120 × 0.02 = 2.4
Step 3: Contribution per order
What a strong candidate does: Gross profit minus picking, delivery and payment.
Contribution per order (BRL): 26.4 - 6 - 9 - 2.4 = 9
Step 4: Breakeven orders per month
What a strong candidate does: Fixed costs divided by contribution.
Breakeven orders per month: 90,000 ÷ 9 = 10,000
Step 5: Per day
What a strong candidate does: Over a 30-day month.
Breakeven orders per day: 10,000 ÷ 30 = 333

The recommendation to listen for

At the end, say: "The CEO walks in. What is your recommendation?"

The grocer should open more dark stores only where each can reach about 333 orders a day, because each order contributes just BRL 9 against BRL 90,000 of monthly fixed cost per store. This means a store needs 10,000 orders a month to break even; below that it loses money even though every order is profitable. The main levers are bigger baskets, which spread the BRL 9 delivery cost, and denser neighbourhoods. The risk is that discounts used to build volume cut the contribution further. As a next step, track daily orders per store against the 333 threshold.

Score the candidate

Score each criterion from 1 to 5. A 2 or a 4 sits between the descriptions.

This case has no exhibit. Score Exhibit reading on how the candidate used the data you gave them: did they pick out the number that matters and say what it means?

Structuring

1: No clear structure, or a memorized framework that does not fit the problem.
3: A sensible structure, but with some overlap, a gap, or no clear priority.
5: A structure built for this problem, with no overlap and no gaps, a stated hypothesis, and a clear first step.

Math

1: Frequent errors, no units, or needed heavy help to finish.
3: Right answers but slow or messy working, or one error caught late.
5: Accurate and clearly narrated, with units, a sense check, and what the number means.

Exhibit reading

1: Read the chart aloud without finding the number that matters.
3: Found the key number but gave only part of the so-what.
5: Pulled the right number quickly and said what it means for the case.

Synthesis

1: Summarized what was done, with no clear answer.
3: Gave an answer, but with weak reasons or no next step.
5: Answer first, then two or three reasons with numbers, the main risk, and next steps.

Communication

1: Hard to follow: long silences, no signposting.
3: Clear most of the time, with some rambling.
5: Calm and concise, signposted each step, and checked in with the interviewer.

Total

0 out of 25

Score all five criteria to see the band and the feedback template.