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UiPath·Machine Learning Engineer·Technical Phone Screen·Intermediate

Intermediate
Jul 2026

Summary

Interviewed for an ML Engineer role at UiPath and got a probability question that felt more like a stats refresher than anything ML-specific. Pretty straightforward if you remember your independence rules.

Questions Asked (1)

Q1

You roll two fair six-sided dice twice (four total die rolls). What is the probability that all four outcomes are even?

Algorithms & Data Structures
Author's notes

Each die has a 1/2 shot at landing even, and since the rolls don't affect each other, you just multiply (1/2) four times and get 1/16.

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AI HintsAI Generated

Suggested Approach

Recognize that each die roll is independent and has a 1/2 chance of being even. Since there are four independent rolls, multiply the probabilities together to get (1/2)^4 = 1/16. Alternatively, note that the total number of outcomes is 6^4 and the number of favorable outcomes is 3^4, giving 3^4/6^4 = 1/16.

Pro tip: State the independence assumption explicitly and simplify the fraction to show you're detail-oriented. Mention that the grouping into two rolls of two dice doesn't affect the probability because each die is independent.

1. Identify the probability for a single die

A fair six-sided die has three even numbers (2, 4, 6), so the probability of rolling an even number is 3/6 = 1/2.

2. Recognize independence

Each die roll is independent, so the outcome of one roll does not affect the others. The grouping into two rolls of two dice is irrelevant.

3. Multiply probabilities

For independent events, multiply the individual probabilities: (1/2) * (1/2) * (1/2) * (1/2) = (1/2)^4 = 1/16.

4. Verify with counting (optional)

Alternatively, compute the total number of outcomes (6^4 = 1296) and the number of favorable outcomes (3^4 = 81), then divide: 81/1296 = 1/16.

Key Points to Mention

  • Independence of die rolls
  • Probability of even on a single die is 1/2
  • Multiplication rule for independent events
  • Total outcomes vs. favorable outcomes (combinatorial approach)
  • Simplification of the final fraction
  • The grouping of rolls does not affect the probability

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