Question 648 of 1,040
Design Cost-Optimized ArchitecturesmediumMultiple SelectObjective-mapped

SAA-C03 Design Cost-Optimized Architectures Practice Question

This SAA-C03 practice question tests your understanding of design cost-optimized architectures. 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 company is running a production web application on Amazon EC2 instances behind an Application Load Balancer (ALB). The workload has predictable traffic spikes during business hours and low traffic at night. The current architecture uses On-Demand EC2 instances, leading to high costs. The company wants to reduce costs without sacrificing availability or performance. Which three of the following strategies would help achieve this goal? (Choose three.)

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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

Purchase Reserved Instances for the baseline capacity that runs 24/7.

Purchasing Reserved Instances for the baseline 24/7 capacity provides a significant discount (up to 72%) compared to On-Demand pricing, directly reducing costs for the always-running portion of the workload. This strategy is correct because it matches the predictable, steady-state traffic component without sacrificing availability or performance.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates may think Spot Instances can be used for the entire workload during peak hours, but they overlook the interruption risk and the requirement for the workload to be fault-tolerant, which a production web application behind an ALB typically is not without careful design.

Detailed technical explanation

How to think about this question

Reserved Instances apply a billing discount to a specific instance family and size in a given Availability Zone or region, and they can be purchased with All Upfront, Partial Upfront, or No Upfront payment options. Auto Scaling with a mixed instances policy allows you to define a percentage split between On-Demand and Spot Instances, and the Spot Instances can be diversified across multiple instance types and purchase pools to reduce the chance of interruption. Scheduled scaling actions use CloudWatch alarms or cron-like schedules to adjust the desired capacity at specific times, ensuring capacity is added before business hours and removed after, which aligns with the predictable traffic pattern described.

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

A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.

What to study next

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FAQ

Questions learners often ask

What does this SAA-C03 question test?

Design Cost-Optimized Architectures — This question tests Design Cost-Optimized Architectures — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Purchase Reserved Instances for the baseline capacity that runs 24/7. — Purchasing Reserved Instances for the baseline 24/7 capacity provides a significant discount (up to 72%) compared to On-Demand pricing, directly reducing costs for the always-running portion of the workload. This strategy is correct because it matches the predictable, steady-state traffic component without sacrificing availability or performance.

What should I do if I get this SAA-C03 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.

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Last reviewed: Jun 11, 2026

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This SAA-C03 practice question is part of Courseiva's free Amazon Web Services 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 SAA-C03 exam.