Google PCA Practice Question: Analysing and Optimising Technical and Business Processes
A company runs batch analytics workloads on Compute Engine that can tolerate interruptions. They want to reduce compute costs by up to 60-90%. Which compute option is the most cost-effective?
⚠ Common exam trap
PCA often tests the distinction between discount mechanisms — candidates confuse sustained use discounts (automatic, ~30%) and committed use discounts (contractual, ~57%) with preemptible/spot pricing (up to 91%), and forget that preemptible VMs require fault-tolerant workloads.
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
✓
Preemptible VMs
Preemptible VMs are Google's spot-equivalent instances that can be terminated at any time when resources are needed elsewhere, and they offer discounts of up to 60-91% compared to on-demand pricing. Since the batch analytics workloads are explicitly described as interruption-tolerant, they are the ideal fit for preemptible VMs, which is why they deliver the greatest cost savings here.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
On-demand VMs
Why it's wrong here
On-demand VMs bill at full list price with no interruption tolerance exploited, so they deliver none of the 60-90% saving the workload's fault-tolerant nature permits. They suit short-lived or unpredictable jobs that cannot be preempted, not batch analytics where Spot VMs would capture the discount.
- ✗
Committed use discounts (1-year)
Why it's wrong here
Committed use discounts apply to steady, predictable baseline usage and require a one-year spend commitment, so they do not suit interruptible batch jobs and cannot reach 60-90% savings. They tempt because they cut costs substantially; they would be correct for continuously running workloads with stable resource consumption.
- ✓
Preemptible VMs
Why this is correct
Preemptible VMs offer up to 80% discounts versus standard instances, directly meeting the 60–90% cost-reduction constraint. They suit interruption-tolerant batch analytics because Compute Engine terminates them after 24 hours maximum, with 30-second preemption notice. This makes them the cheapest option for workloads that can checkpoint and resume.
- ✗
Sustained use discounts
Why it's wrong here
Sustained use discounts apply automatically to steady, always-on monthly usage of standard VMs, capping at around 30% and requiring continuous consumption rather than interruption tolerance. Spot VMs, which exploit the workload's tolerance of preemption, deliver the 60-90% reduction instead.
Go deeper
Related to this question
Learn chapter
Google Kubernetes Engine (GKE)
Key term
Compute Engine
Compute Engine is Google Cloud's Infrastructure-as-a-Service (IaaS) offering that lets you create and run virtual machines on Google's infrastructure.
Key term
CAN
A CAN (Controller Area Network) is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other without a host computer.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Google Cloud exam blueprint
This PCA 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 PCA exam.