10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
These 10 free PMLE questions are organized by exam domain, so you can see how each part of the Professional Machine Learning Engineer blueprint is tested. Reveal the answer and explanation under each question.
Domain 1: Architecting low-code AI solutions (~13%)
Question 1
Promotion schedules for a product are fixed fourteen days in advance. Its daily demand depends on both recent demand and the planned discount. A SQL team keeps the sales history in BigQuery and wants a warehouse-native forecasting model that represents the time-series structure while incorporating those known future discounts. Which training and inference combination fits this requirement?
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Correct answer: A - Train ARIMA_PLUS_XREG and call ML.FORECAST with future dates and the corresponding planned discount values.
Question 2
OCR recognizes the text in a distributor's invoices accurately, yet the downstream extraction code frequently associates a line-item amount with the wrong description when suppliers change layouts. The team needs typed invoice fields and correctly grouped line items, has no custom-labeled training corpus, and wants the least custom development before a representative pilot. Which starting approach is most appropriate?
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Correct answer: D - Pilot a pretrained Document AI invoice processor, checking its extracted fields and line-item groups against representative invoices.
Domain 2: Collaborating within and across teams to manage data and models (~16%)
Question 3
For a checkout decision made at 09:00, an offline training query reconstructs the shopper's failed-payment count. Three feature records exist: count 2, event time 08:50, available to the prediction service at 08:52; count 4, event time 08:58, available at 09:04; count 5, event time 09:02, available at 09:03. The query currently chooses count 4 because its event time precedes checkout. How should the feature be reconstructed to retain useful history without giving training information that serving could not have known?
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Correct answer: D - Use count 2, selecting the latest feature value that was actually available when the checkout decision was made.
Question 4
A fraud team compares four score thresholds on the same fully labeled validation batch. Every flagged payment requires review, and the team can review at most 1,100 payments per batch. Its decision model assigns a $4 cost to each false positive and a $40 cost to each false negative; no other costs differ between thresholds. Results are:
Threshold 0.20: TP 380, FP 1,820, FN 20.
Threshold 0.40: TP 360, FP 640, FN 40.
Threshold 0.60: TP 320, FP 180, FN 80.
Threshold 0.80: TP 240, FP 60, FN 160.
Which threshold minimizes modeled error cost while respecting review capacity?
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Correct answer: C - Threshold 0.60.
Domain 3: Scaling prototypes into ML models (~21%)
Question 5
Prompt revisions have stopped improving a Gemini support assistant. Error analysis shows that the correct, current manual passages are already retrieved, but the model repeatedly assigns the wrong resolution category under a stable company taxonomy. The team has thousands of expert-reviewed input-response examples and a separate evaluation set. Manuals change weekly; the categorization rules do not. What experiment targets the remaining failure while preserving access to current product facts?
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Correct answer: B - Run supervised tuning on the reviewed examples, retaining retrieval for current manuals and evaluating against the baseline.
Question 6
A profiler from a custom image-training job shows long gaps between GPU kernels and GPU utilization near 20%. One decoding worker saturates a CPU core while other CPU cores are idle; storage reads are fast. Replacing the real input stream with pre-generated tensors raises GPU utilization above 90% without changing the model or batch size. Given this controlled comparison, where should the engineer spend the next optimization effort?
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Correct answer: C - Parallelize decoding and prefetch prepared batches to keep the accelerator supplied with data.
Domain 4: Serving and scaling models (~20%)
Question 7
Unpredictable 45-second traffic bursts push an online prediction service beyond its 150 ms p95 latency objective. The Gemini Enterprise Agent Platform deployment keeps two replicas running and permits up to twelve. During a burst, the two replicas are compute-saturated; additional replicas need 75 seconds to load the model. Load tests with eight already-running replicas meet the objective, and quota is available. Without changing the model or the latency objective, which configuration change addresses the measured bottleneck?
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Correct answer: C - Maintain eight ready replicas and allow scaling to twelve by raising the deployment's minimum replica count.
Question 8
A recommendation team proposes a 50/50 endpoint traffic split to compare weekly purchase conversion per user. Individual users make many requests and can receive recommendations from both model versions within the same shopping journey. Serving reliability has already been validated; the remaining question is whether the candidate changes user behavior. Which assignment design supports that comparison?
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Correct answer: B - Randomly assign each user to one model and preserve that assignment for the whole experiment.
Domain 5: Automating and orchestrating ML pipelines (~18%)
Question 9
Yesterday's preprocessing output appears in today's training run even though new source records passed data-quality checks. The Gemini Enterprise Agent Platform Pipelines component receives the plain string source_uri='gs://ml-inputs/current.csv'; that object is overwritten daily. The component's image, parameters, and source_uri are unchanged, and its execution is marked as a cache hit. The team wants to retain reuse when inputs truly have not changed. What is the durable correction?
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Correct answer: A - Publish immutable data snapshots and pass each snapshot's distinct identity as an explicit component input.
Domain 6: Monitoring AI solutions (~13%)
Question 10
An incident investigation confirms that instructions hidden in a retrieved vendor document caused a support agent to export customer records to an unauthorized external destination. Model Armor screens user prompts and final answers, but export-tool calls use a broadly privileged service account and do not check the requesting user's permissions. The export path remains enabled. Which response should take priority to contain this data-loss path?
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Correct answer: B - Disable the export path immediately and require caller and destination authorization before restoring the tool.
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The full bank has 1,020 more PMLE questions with explanations.