- A
30
Why wrong: 30 usable addresses correspond to a /27 subnet (5 host bits), which is insufficient for 50 devices.
- B
62
Correct. /26 provides 62 usable addresses, enough for 50 devices with room for growth.
- C
126
Why wrong: 126 usable addresses come from a /25 subnet (7 host bits), which is larger than necessary.
- D
254
Why wrong: 254 usable addresses are from a /24 subnet (8 host bits), which is much larger than required.
Quick Answer
The answer is 62 usable host addresses. This is correct because a /26 subnet mask leaves 6 bits for host addresses, calculated as 2^(32-26) = 2^6 = 64 total addresses per subnet, from which you must subtract the network address and the broadcast address, leaving 62 usable hosts. On the CompTIA Network+ N10-009 exam, this concept tests your ability to apply subnetting fundamentals quickly, often in scenario-based questions where you must determine if a given subnet supports a required number of devices. A common trap is forgetting to subtract the two reserved addresses, leading to an overcount of 64. To avoid this, remember the memory tip: "Total addresses minus two, that's what you can use." For a /26, think of the 6 host bits as giving you 64 total, then drop the first and last—leaving 62 for your devices.
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 engineer is designing a subnet to accommodate 50 devices in a single broadcast domain. The engineer uses a /26 subnet mask. How many usable host addresses are available?
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
62
A /26 subnet mask provides 2^(32-26) = 64 total addresses. Subtracting the network and broadcast addresses leaves 62 usable host addresses. This is sufficient for 50 devices in a single broadcast domain.
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.
- ✗
30
Why it's wrong here
30 usable addresses correspond to a /27 subnet (5 host bits), which is insufficient for 50 devices.
- ✓
62
Why this is correct
Correct. /26 provides 62 usable addresses, enough for 50 devices with room for growth.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
126
Why it's wrong here
126 usable addresses come from a /25 subnet (7 host bits), which is larger than necessary.
- ✗
254
Why it's wrong here
254 usable addresses are from a /24 subnet (8 host bits), which is much larger than required.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often forget to subtract the network and broadcast addresses, or they confuse the total addresses (64) with usable addresses (62), leading them to pick 64 or misapply the formula for a different prefix length.
Detailed technical explanation
How to think about this question
The /26 mask (255.255.255.192) borrows 2 bits from the host portion of a Class C address, creating 4 subnets each with 64 addresses. The usable host count is always 2^(32-prefix) - 2, where the -2 accounts for the network and broadcast addresses. In real-world scenarios, engineers must also account for gateway addresses, DHCP reservations, and management IPs when sizing subnets.
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.
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: 62 — A /26 subnet mask provides 2^(32-26) = 64 total addresses. Subtracting the network and broadcast addresses leaves 62 usable host addresses. This is sufficient for 50 devices in a single broadcast domain.
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 →
Same concept, more angles
1 more ways this is tested on N10-009
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A network administrator is configuring IP addresses for a new subnet. The network address is 192.168.1.0 with a subnet mask of 255.255.255.240. How many usable host addresses are available on this subnet?
easy- ✓ A.14
- B.16
- C.30
- D.62
Why A: The subnet mask 255.255.255.240 (or /28) provides 16 total addresses per subnet. The network address (192.168.1.0) and the broadcast address (192.168.1.15) are reserved, leaving 16 - 2 = 14 usable host addresses. This is calculated as 2^(32-28) - 2 = 2^4 - 2 = 16 - 2 = 14.
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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