AWS Certified Cloud Practitioner — Question 494

A company has two AWS accounts in an organization in AWS Organizations for consolidated billing. All of the company’s AWS resources are hosted in one AWS Region.

Account A has purchased five Amazon EC2 Standard Reserved Instances (RIs) and has four EC2 instances running. Account B has not purchased any RIs and also has four EC2 instances running.

Which statement is true regarding pricing for these eight instances?

Answer options

• A. The eight instances will be charged as regular instances.
• B. Four instances will be charged as RIs, and four will be charged as regular instances.
• C. Five instances will be charged as RIs, and three will be charged as regular instances.
• D. The eight instances will be charged as RIs.

Correct answer: C

Explanation

In AWS Organizations with consolidated billing enabled, Reserved Instance (RI) discounts are shared across all member accounts within the same AWS Region. Account A uses four of its five RIs, leaving one unused RI that automatically applies to one of Account B's four running instances. Consequently, a total of five instances (four in Account A and one in Account B) are billed at the RI rate, while the remaining three instances in Account B are charged at the standard On-Demand rate.