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 of 255.255.255.240 corresponds to a /28 prefix length, allocating 4 bits for host addressing in each subnet.. 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 host uses the subnet mask 255.255.255.240. How many usable host addresses exist in each subnet?
12
Why wrong: This is wrong because 12 does not match the /28 calculation.
14
This is correct because a /28 has 16 total addresses minus 2 reserved equals 14 usable hosts.
16
Why wrong: This is wrong because 16 is the total block size, not the usable count.
30
Why wrong: This is wrong because 30 usable hosts corresponds to a /27 subnet.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
14
The mask 255.255.255.240 corresponds to /28. In practical terms, that leaves 4 host bits, which gives 16 total addresses in each subnet. After subtracting the network and broadcast addresses, 14 usable hosts remain. This is a classic host-capacity calculation and a very common subnetting pattern on the exam.
Key principle: A subnet mask of 255.255.255.240 corresponds to a /28 prefix length, allocating 4 bits for host addressing in each subnet.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
12
Why it's wrong here
This is wrong because 12 does not match the /28 calculation.
When this WOULD be correct
This option would be correct in a scenario where the question mistakenly asks for the total number of addresses in the subnet instead of usable addresses. For example, if the question stated, 'How many total addresses exist in a subnet with a mask of 255.255.255.240?' then 16 would be the correct answer.
14
Why this is correct
This is correct because a /28 has 16 total addresses minus 2 reserved equals 14 usable hosts.
Related concept
A subnet mask of 255.255.255.240 corresponds to a /28 prefix length, allocating 4 bits for host addressing in each subnet.
16
Why it's wrong here
This is wrong because 16 is the total block size, not the usable count.
When this WOULD be correct
If the question asked about the total number of addresses in a subnet with a mask of 255.255.255.240, then the correct answer would be 16, as it counts all addresses including the network and broadcast addresses.
30
Why it's wrong here
This is wrong because 30 usable hosts corresponds to a /27 subnet.
When this WOULD be correct
If the question specified a subnet mask of 255.255.255.252, which allows for 4 total addresses, then option D would be correct, as there would be 2 usable host addresses in that subnet.
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 /28 has 16 total addresses minus 2 reserved equals 14 usable hosts.
Why this is wrong here
Option A is incorrect because the subnet mask 255.255.255.240 allows for 16 total addresses in each subnet, but only 14 of those are usable for hosts after accounting for the network and broadcast addresses.
★ When this WOULD be the correct answer
This option would be correct in a scenario where the question mistakenly asks for the total number of addresses in the subnet instead of usable addresses. For example, if the question stated, 'How many total addresses exist in a subnet with a mask of 255.255.255.240?' then 16 would be the correct answer.
Why candidates choose this
Candidates may choose this option due to confusion between total addresses and usable addresses, leading them to incorrectly calculate the usable host count without considering the network and broadcast addresses.
Why this is wrong here
This option is wrong because a subnet mask of 255.255.255.240 allows for 16 total IP addresses in each subnet, but only 14 of those are usable due to the network and broadcast addresses being reserved.
★ When this WOULD be the correct answer
If the question asked about the total number of addresses in a subnet with a mask of 255.255.255.240, then the correct answer would be 16, as it counts all addresses including the network and broadcast addresses.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of how to calculate usable addresses versus total addresses, leading them to mistakenly count all addresses in the subnet.
Why this is wrong here
Option D is incorrect because the subnet mask 255.255.255.240 allows for 16 total addresses in each subnet, but only 14 of those are usable for hosts after accounting for the network and broadcast addresses.
★ When this WOULD be the correct answer
If the question specified a subnet mask of 255.255.255.252, which allows for 4 total addresses, then option D would be correct, as there would be 2 usable host addresses in that subnet.
Why candidates choose this
Candidates might choose option D because they miscalculate the total number of addresses without considering the reserved network and broadcast addresses, leading them to believe that all addresses are usable.
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
A frequent exam trap is selecting the total number of addresses in the subnet (16) instead of the usable host addresses (14). Candidates often forget to subtract the network and broadcast addresses, which are reserved and cannot be assigned to hosts. Another common mistake is confusing the /28 subnet mask with /27, which offers 30 usable hosts, leading to incorrect answers like 30. This confusion arises because both subnet masks are close in size but differ significantly in host capacity. Always remember that usable hosts equal total addresses minus two reserved addresses.
Detailed technical explanation
Subnetting is a fundamental networking concept that divides a larger IP network into smaller, manageable sub-networks or subnets. The subnet mask 255.255.255.240 corresponds to a /28 prefix length, meaning the first 28 bits are fixed for network identification, and the remaining 4 bits are available for host addressing. This mask is commonly used to create multiple small subnets within a larger network, optimizing IP address allocation and improving network performance and security. The calculation of usable host addresses in a subnet follows a standard formula: 2^n - 2, where n is the number of host bits. For a /28 mask, 4 bits are available for hosts, resulting in 2^4 = 16 total addresses. Subtracting 2 addresses reserved for the network identifier and broadcast address leaves 14 usable host addresses per subnet. This rule is critical in Cisco networking and the CCNA exam to correctly design and troubleshoot IP addressing schemes. A common exam trap is confusing the total number of addresses with usable hosts. For example, 16 addresses include network and broadcast addresses, which cannot be assigned to hosts. Another frequent mistake is mixing subnet masks, such as confusing /28 with /27, which provides 30 usable hosts. Understanding the distinction between total and usable addresses and applying the correct subnet mask is essential for accurate subnetting and avoiding errors in Cisco network configurations.
Key takeaway
A subnet mask of 255.255.255.240 corresponds to a /28 prefix length, allocating 4 bits for host addressing in each subnet.
Real-world example
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Review a subnet mask of 255.255.255.240 corresponds to a /28 prefix length, allocating 4 bits for host addressing in each subnet., 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 of 255.255.255.240 corresponds to a /28 prefix length, allocating 4 bits for host addressing in each subnet..
The correct answer is: 14 — The mask 255.255.255.240 corresponds to /28. In practical terms, that leaves 4 host bits, which gives 16 total addresses in each subnet. After subtracting the network and broadcast addresses, 14 usable hosts remain. This is a classic host-capacity calculation and a very common subnetting pattern on the exam.
Review a subnet mask of 255.255.255.240 corresponds to a /28 prefix length, allocating 4 bits for host addressing in each subnet., then practise related 200-301 questions on the same topic to reinforce the concept.
A subnet mask of 255.255.255.240 corresponds to a /28 prefix length, allocating 4 bits for host addressing in each subnet.
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Last reviewed: May 17, 2026
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