Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A company needs a subnet that will support exactly 50 devices. Which subnet mask provides the minimum number of usable host addresses while still accommodating the requirement?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
255.255.255.128 (/25)
/25 provides 126 usable hosts, which is more than needed and wastes addresses.
B
Best answer
255.255.255.192 (/26)
/26 provides 62 usable hosts, which is the smallest subnet that can accommodate 50 devices.
C
Distractor review
255.255.255.224 (/27)
/27 only provides 30 usable hosts, which is too few.
D
Distractor review
255.255.255.240 (/28)
/28 only provides 14 usable hosts, far too few.
Common exam trap
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Technical deep dive
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
- CIDR notation defines the prefix length.
- Block size helps identify subnet boundaries.
- Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
- The required host count determines the smallest suitable subnet.
TExam Day Tips
- Write the block size before choosing the subnet.
- Check whether the question asks for hosts, subnets or a specific address range.
- Do not confuse /24, /25, /26 and /27 host counts.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
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Question 2
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Question 3
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Question 4
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Question 5
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Question 6
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FAQ
Questions learners often ask
What does this N10-009 question test?
CIDR notation defines the prefix length.
What is the correct answer to this question?
The correct answer is: 255.255.255.192 (/26) — To support 50 devices, the subnet must have at least 50 usable host addresses. A /26 subnet (255.255.255.192) provides 64 total addresses, with 62 usable (subtracting network and broadcast addresses), which meets the need with minimal waste. /25 gives 126 usable hosts, too many; /27 gives only 30; /28 gives 14.
What should I do if I get this N10-009 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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