Capital One·Data Scientist·Technical Phone Screen·Intermediate

Intermediate

Jun 2026

Summary

Capital One Data Scientist interview that leaned harder into financial modeling than I expected. The core question was a renewable energy plant ROI case, and you basically had to work through the math live to figure out whether the investment made sense.

Questions Asked (1)

A renewable energy plant has an average output of 1,000 kWh, a max annual capacity of 8.8 million kWh, a monthly land lease of $5M, fixed annual costs of $25M, variable cost of $20/kWh, and a selling price of $40/kWh. The initial investment is $400M. What is the minimum annual kWh output the plant needs to generate and sell to hit a 10% annual ROI? And given that number relative to the 8.8M kWh capacity ceiling, would you approve the investment?

Pricing & MonetizationProduct Analytics & MetricsProduct Strategy

Author's notes

I knew the ROI formula but blanked for a second on how to wire up all the cost components cleanly.

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AI HintsAI Generated

Suggested Approach

First, compute the annual fixed costs including land lease and fixed costs, then set up the profit equation: Profit = Revenue - Variable Costs - Fixed Costs. Set Profit equal to 10% of initial investment ($40M) and solve for the required annual kWh output. Finally, compare this required output to the 8.8M kWh capacity ceiling to decide if the investment is feasible.

Pro tip: Always clarify whether the 10% ROI is on the initial investment or on total costs, and state your assumption explicitly. Also, double-check units: land lease is monthly, so multiply by 12 to get annual.

1. Calculate annual fixed costs

Sum the annual land lease (monthly lease × 12) and fixed annual costs to get total fixed costs per year.

2. Determine target profit

Compute the required annual profit as 10% of the initial investment ($400M × 0.10 = $40M).

3. Set up profit equation

Profit = (Selling price - Variable cost) × Quantity - Fixed costs. Plug in known values and set profit equal to target profit.

4. Solve for required quantity

Solve the equation for Quantity (annual kWh output). This is the minimum output needed to achieve the target ROI.

5. Compare to capacity and decide

Check if the required quantity is less than or equal to the max annual capacity (8.8M kWh). If yes, the investment is feasible; otherwise, it is not.

Key Points to Mention

Annualizing the monthly land lease ($5M × 12 = $60M per year).
Contribution margin per kWh: selling price minus variable cost ($40 - $20 = $20/kWh).
Total annual fixed costs: $60M + $25M = $85M.
Target profit: 10% of $400M = $40M.
Required quantity: (Fixed costs + Target profit) / Contribution margin = ($85M + $40M) / $20 = 6.25M kWh.
Comparison to capacity: 6.25M kWh < 8.8M kWh, so the investment is feasible.
Consideration of whether the average output of 1,000 kWh (likely per hour or per day?) is relevant; clarify units if needed.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.