This 200-301 practice question tests your understanding of network infrastructure and connectivity. 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. A key principle to apply: a subnet mask defines how many bits of an IP address are used for the network versus the host portion, directly affecting subnet size.. 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 subnet uses the mask 255.255.255.224. How many usable host addresses does it provide?
14
Why wrong: This is wrong because 14 usable hosts would correspond to a /28, not a /27.
30
This is correct because a /27 has 32 total addresses and 30 usable host addresses.
62
Why wrong: This is wrong because 62 usable hosts would correspond to a /26.
126
Why wrong: This is wrong because 126 usable hosts would correspond to a /25.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
30
A mask of 255.255.255.224 corresponds to a /27 prefix. In plain language, that leaves 5 host bits available in the address, which creates 32 total addresses in each subnet. Two of those are reserved: one for the network address and one for the broadcast address. That leaves 30 usable host addresses. This is a classic subnetting question because it tests whether you can move from mask to prefix idea to host count without getting lost. Many learners remember the block size but forget to subtract the network and broadcast entries. The correct answer comes from that full logic chain: /27 means 32 total, and therefore 30 usable.
Key principle: A subnet mask defines how many bits of an IP address are used for the network versus the host portion, directly affecting subnet size.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
14
Why it's wrong here
This is wrong because 14 usable hosts would correspond to a /28, not a /27.
When this WOULD be correct
This option would be correct in a scenario where the question specifies a subnet mask of 255.255.255.240, which allows for 14 usable host addresses. In this case, the calculation would be 2^(4) - 2 = 14.
30
Why this is correct
This is correct because a /27 has 32 total addresses and 30 usable host addresses.
Related concept
A subnet mask defines how many bits of an IP address are used for the network versus the host portion, directly affecting subnet size.
62
Why it's wrong here
This is wrong because 62 usable hosts would correspond to a /26.
When this WOULD be correct
If the question asked about a subnet mask of 255.255.255.192 instead, which provides 62 usable addresses, then option C would be the correct answer. In this case, the calculation would be 2^(32-26) - 2 = 62 usable addresses.
126
Why it's wrong here
This is wrong because 126 usable hosts would correspond to a /25.
When this WOULD be correct
If the question asked how many usable addresses are in a subnet with a mask of 255.255.255.0, which allows for 256 total addresses minus 2 for the network and broadcast addresses, then option D would be correct as it would provide 254 usable addresses.
Option-by-option analysis
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
Why this is correct
This is correct because a /27 has 32 total addresses and 30 usable host addresses.
Why this is wrong here
This option is wrong because a subnet mask of 255.255.255.224 provides 30 usable host addresses, not 14. The calculation is based on the formula 2^(number of host bits) - 2, where the number of host bits is 5 for this subnet mask.
★ When this WOULD be the correct answer
This option would be correct in a scenario where the question specifies a subnet mask of 255.255.255.240, which allows for 14 usable host addresses. In this case, the calculation would be 2^(4) - 2 = 14.
Why candidates choose this
Candidates may choose this option due to confusion between different subnet masks and their corresponding usable addresses, particularly if they miscalculate or misremember the formula for determining usable hosts.
Why this is wrong here
This option is wrong because a subnet mask of 255.255.255.224 allows for 32 total addresses, of which 30 are usable after subtracting the network and broadcast addresses. The calculation is 2^(32-27) - 2 = 30 usable addresses.
★ When this WOULD be the correct answer
If the question asked about a subnet mask of 255.255.255.192 instead, which provides 62 usable addresses, then option C would be the correct answer. In this case, the calculation would be 2^(32-26) - 2 = 62 usable addresses.
Why candidates choose this
Candidates may choose this option due to confusion between subnet sizes and their corresponding usable addresses, especially if they have recently studied larger subnets and misapplied the calculations.
Why this is wrong here
Option D is incorrect because a subnet mask of 255.255.255.224 allows for 30 usable host addresses, not 126. The calculation is based on the formula 2^(32 - subnet bits) - 2, where the subnet bits for this mask is 27.
★ When this WOULD be the correct answer
If the question asked how many usable addresses are in a subnet with a mask of 255.255.255.0, which allows for 256 total addresses minus 2 for the network and broadcast addresses, then option D would be correct as it would provide 254 usable addresses.
Why candidates choose this
Candidates may choose this option due to confusion with larger subnet sizes, mistakenly associating the number 126 with a common subnet size, or miscalculating the usable hosts based on a misunderstanding of subnetting principles.
Analysis generated from the official 200-301blueprint 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
Remember to subtract the network and broadcast addresses from the total count of addresses in a subnet.
Detailed technical explanation
Subnetting is a fundamental concept in networking that divides a larger IP network into smaller, manageable segments called subnets. Each subnet uses a subnet mask to determine which portion of the IP address represents the network and which portion represents hosts. The subnet mask 255.255.255.224 corresponds to a /27 prefix length, meaning the first 27 bits are the network portion and the remaining 5 bits are for host addresses. The number of usable host addresses in a subnet is calculated by taking 2 to the power of the number of host bits and subtracting 2 for the network and broadcast addresses. For a /27 subnet mask, there are 5 host bits, so 2^5 equals 32 total addresses. Subtracting 2 leaves 30 usable host addresses. This calculation is critical for designing networks that require specific numbers of hosts per subnet. A common exam trap is confusing the subnet mask with similar masks like /26 or /28, which have different host counts. For example, a /26 mask provides 62 usable hosts, and a /28 provides 14. Misremembering these values or forgetting to subtract the network and broadcast addresses leads to incorrect answers. Practically, Cisco devices use this logic to allocate IP addresses efficiently and avoid address conflicts within subnets.
Key takeaway
A subnet mask defines how many bits of an IP address are used for the network versus the host portion, directly affecting subnet size.
Real-world example
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
Review a subnet mask defines how many bits of an IP address are used for the network versus the host portion, directly affecting subnet size., then practise related 200-301 questions on the same topic to reinforce the concept.
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FAQ
Network Infrastructure and Connectivity — This question tests Network Infrastructure and Connectivity — A subnet mask defines how many bits of an IP address are used for the network versus the host portion, directly affecting subnet size..
The correct answer is: 30 — A mask of 255.255.255.224 corresponds to a /27 prefix. In plain language, that leaves 5 host bits available in the address, which creates 32 total addresses in each subnet. Two of those are reserved: one for the network address and one for the broadcast address. That leaves 30 usable host addresses. This is a classic subnetting question because it tests whether you can move from mask to prefix idea to host count without getting lost. Many learners remember the block size but forget to subtract the network and broadcast entries. The correct answer comes from that full logic chain: /27 means 32 total, and therefore 30 usable.
Review a subnet mask defines how many bits of an IP address are used for the network versus the host portion, directly affecting subnet size., then practise related 200-301 questions on the same topic to reinforce the concept.
A subnet mask defines how many bits of an IP address are used for the network versus the host portion, directly affecting subnet size.
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Last reviewed: May 17, 2026
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