- A
Deploy a Deep Learning Recommendation Model (DLRM) for prediction
Why wrong: DLRM is for CTR prediction, not retrieval, and may be overkill.
- B
Use a contextual bandit algorithm for exploration only
Why wrong: Bandits are for exploration, not for generating personalized recommendations from a large corpus.
- C
Use matrix factorization with collaborative filtering
Why wrong: Matrix factorization cannot use side features for cold start and is not real-time.
- D
Implement a two-tower model (user and item towers) with embeddings and nearest neighbor search
Two-tower models can incorporate side features and enable fast retrieval.
PMLE Solving business challenges with ML Practice Question
This PMLE practice question tests your understanding of solving business challenges with ml. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A media company wants to build a real-time recommendation system for articles. They have a large user base (10M+) and frequent updates to user interactions. They need to handle cold-start users and new articles. Which architecture on Vertex AI is most suitable?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Implement a two-tower model (user and item towers) with embeddings and nearest neighbor search
The two-tower model (user and item towers) with embeddings and nearest neighbor search is the most suitable because it handles cold-start users and new articles by learning separate embeddings for users and items, enabling efficient retrieval via approximate nearest neighbor (ANN) search. This architecture supports real-time updates and scales to 10M+ users by decoupling user and item representations, allowing incremental training on new interactions without full retraining.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Deploy a Deep Learning Recommendation Model (DLRM) for prediction
Why it's wrong here
DLRM is for CTR prediction, not retrieval, and may be overkill.
- ✗
Use a contextual bandit algorithm for exploration only
Why it's wrong here
Bandits are for exploration, not for generating personalized recommendations from a large corpus.
- ✗
Use matrix factorization with collaborative filtering
Why it's wrong here
Matrix factorization cannot use side features for cold start and is not real-time.
- ✓
Implement a two-tower model (user and item towers) with embeddings and nearest neighbor search
Why this is correct
Two-tower models can incorporate side features and enable fast retrieval.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that matrix factorization (Option C) is sufficient for cold-start scenarios, but candidates miss that it requires retraining on new data and cannot generate embeddings for unseen users or items without side features.
Detailed technical explanation
How to think about this question
The two-tower model computes user and item embeddings separately, often using deep neural networks, and then uses dot product or cosine similarity for scoring. For real-time inference, embeddings are precomputed and indexed using ANN libraries like ScaNN or FAISS, enabling sub-100ms retrieval even with 10M+ items. Cold-start is addressed by using side features (e.g., user demographics, article metadata) in the towers, allowing the model to generate embeddings for new entities without historical interactions.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this PMLE question test?
Solving business challenges with ML — This question tests Solving business challenges with ML — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Implement a two-tower model (user and item towers) with embeddings and nearest neighbor search — The two-tower model (user and item towers) with embeddings and nearest neighbor search is the most suitable because it handles cold-start users and new articles by learning separate embeddings for users and items, enabling efficient retrieval via approximate nearest neighbor (ANN) search. This architecture supports real-time updates and scales to 10M+ users by decoupling user and item representations, allowing incremental training on new interactions without full retraining.
What should I do if I get this PMLE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 30, 2026
This PMLE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PMLE exam.
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