- A
A
Why wrong: /25 provides 126 usable addresses, which is more than necessary but does not represent the smallest subnet meeting the requirement.
- B
B
/26 provides 62 usable addresses, which is the minimum that supports 50 hosts.
- C
C
Why wrong: /27 provides only 30 usable addresses, insufficient for 50 hosts.
- D
D
Why wrong: /28 provides only 14 usable addresses, insufficient for 50 hosts.
Question 484 of 520
N10-009 Networking Concepts Practice Question
This N10-009 practice question tests your understanding of networking concepts. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 network administrator needs to create a subnet that supports exactly 50 hosts. Which subnet mask provides the smallest subnet that meets this requirement?
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
✓
B
Option B is correct because a /26 subnet mask (255.255.255.192) provides 62 usable host addresses (2^(32-26) - 2 = 64 - 2 = 62), which is the smallest subnet that supports at least 50 hosts. A /27 would only provide 30 usable addresses, which is insufficient.
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.
- ✗
A
Why it's wrong here
/25 provides 126 usable addresses, which is more than necessary but does not represent the smallest subnet meeting the requirement.
When this WOULD be correct
Option A would be correct if the question asked for a subnet mask that supports exactly 2 hosts (e.g., for point-to-point links), as a /30 mask provides 2 usable addresses.
- ✓
B
Why this is correct
/26 provides 62 usable addresses, which is the minimum that supports 50 hosts.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
C
Why it's wrong here
/27 provides only 30 usable addresses, insufficient for 50 hosts.
When this WOULD be correct
This subnet mask would be correct if the requirement were to support exactly 30 hosts (e.g., a small branch office with 30 devices).
- ✗
D
Why it's wrong here
/28 provides only 14 usable addresses, insufficient for 50 hosts.
When this WOULD be correct
This subnet mask would be correct if the question required a subnet that supports at least 100 hosts, as it provides 126 usable addresses.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The N10-009 exam frequently reuses these exact scenarios with slightly different constraints.
✓BCorrect answer▾
Why this is correct
/26 provides 62 usable addresses, which is the minimum that supports 50 hosts.
✗AWrong answer — click to see why▾
Why this is wrong here
Option A is wrong because it does not provide a valid subnet mask for 50 hosts; the correct mask must have at least 6 host bits (2^6 - 2 = 62 hosts), such as /26 (255.255.255.192).
★ When this WOULD be the correct answer
Option A would be correct if the question asked for a subnet mask that supports exactly 2 hosts (e.g., for point-to-point links), as a /30 mask provides 2 usable addresses.
Why candidates choose this
Candidates may confuse the number of hosts with the number of addresses or misremember the host bit calculation, thinking a smaller mask like /30 can support 50 hosts.
✗CWrong answer — click to see why▾
Why this is wrong here
This subnet mask provides fewer than 50 usable host addresses (e.g., /27 gives 30 hosts, /26 gives 62 hosts), so it cannot support exactly 50 hosts.
★ When this WOULD be the correct answer
This subnet mask would be correct if the requirement were to support exactly 30 hosts (e.g., a small branch office with 30 devices).
Why candidates choose this
Candidates may miscalculate the number of hosts or confuse the formula (2^n - 2) for host bits, leading them to choose a mask that seems close but is insufficient.
✗DWrong answer — click to see why▾
Why this is wrong here
This subnet mask does not provide exactly 50 hosts; it either provides too few or too many, failing the requirement for the smallest subnet that supports 50 hosts.
★ When this WOULD be the correct answer
This subnet mask would be correct if the question required a subnet that supports at least 100 hosts, as it provides 126 usable addresses.
Why candidates choose this
Candidates may confuse the number of hosts needed with the number of addresses provided by a /25 subnet, or misapply the formula for calculating hosts.
Analysis generated from the official N10-009blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often forget to subtract 2 for the network and broadcast addresses, leading them to choose a /27 (which has 32 total addresses but only 30 usable) thinking it supports 50 hosts.
Detailed technical explanation
How to think about this question
The formula for usable hosts is 2^(32 - prefix_length) - 2, where the subtraction accounts for the network and broadcast addresses. In practice, when planning subnets, you must always consider future growth; a /26 allows for up to 62 hosts, which provides a small buffer beyond the 50-host requirement. This calculation is fundamental to IPv4 subnetting and is directly tested in the CompTIA Network+ N10-009 exam under the Networking Concepts domain.
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 network engineer segments a warehouse floor into three subnets: 20 scanners, 5 printers, and 2 management hosts. Picking the wrong mask wastes addresses or leaves too few usable hosts. Exam questions test whether you can apply CIDR notation, calculate block size, and identify the correct usable-host range for a given prefix.
Visual reference
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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Networking Concepts — study guide chapter
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FAQ
Questions learners often ask
What does this N10-009 question test?
Networking Concepts — This question tests Networking Concepts — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: B — Option B is correct because a /26 subnet mask (255.255.255.192) provides 62 usable host addresses (2^(32-26) - 2 = 64 - 2 = 62), which is the smallest subnet that supports at least 50 hosts. A /27 would only provide 30 usable addresses, which is insufficient.
What should I do if I get this N10-009 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
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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Last reviewed: Jun 11, 2026
This N10-009 practice question is part of Courseiva's free CompTIA 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 N10-009 exam.
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