200-901 Network Fundamentals Practice Question
A network administrator is configuring subnetting for a new branch office that requires 50 usable host addresses per subnet. The available network is 192.168.10.0/24. What subnet mask should be used to meet the requirement with minimal waste?
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
✓
255.255.255.192 (/26)
A /26 mask provides 62 usable hosts (2^(32-26)-2=62), which is the smallest subnet that supports 50 hosts.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
255.255.255.128 (/25)
Why it's wrong here
A /25 mask yields 126 usable host addresses, satisfying 50 but wasting 76 addresses per subnet. It is tempting because it always meets the requirement, but it would be correct where subnets genuinely need between 51 and 126 hosts.
- ✗
255.255.255.224 (/27)
Why it's wrong here
A /27 mask yields 30 usable host addresses, short of the 50 required, so the subnet cannot accommodate the branch. It is tempting because /27 is a common subnetting boundary, but it would be correct where each subnet needs no more than 30 hosts.
- ✓
255.255.255.192 (/26)
Why this is correct
A /26 mask yields 64 addresses, giving 62 usable hosts, which satisfies the 50-host requirement with minimal waste. Smaller masks like /25 waste over 70 addresses; larger masks like /27 provide only 30 usable hosts, falling short.
- ✗
255.255.255.240 (/28)
Why it's wrong here
A /28 mask yields only 14 usable host addresses, far below the 50 required. It is tempting because it conserves address space, but it would be the correct choice for small segments such as point-to-point links or subnets needing at most 14 hosts.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-901 practice question is part of Courseiva's free Cisco 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 200-901 exam.