easyMultiple Choice
200-901 Practice Question: A network administrator needs to assign IP…
A network administrator needs to assign IP addresses to 50 hosts in a subnet. Which subnet mask provides the minimum required number of usable addresses while minimizing waste?
⚠ Common exam trap
Cisco often tests the distinction between 'total addresses' and 'usable addresses' — candidates mistakenly count the total 64 addresses as usable, forgetting to subtract the network and broadcast addresses, or they choose a mask that provides exactly 50 total addresses (which is impossible since host bits must be a power of 2).
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 subnet mask (255.255.255.192) provides 64 total addresses per subnet, of which 62 are usable (2^6 - 2 = 62). This is the smallest power-of-two block that can accommodate 50 hosts, minimizing waste while meeting the requirement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
255.255.255.192 (/26)
Why this is correct
A /26 mask yields 64 addresses, leaving 62 usable after reserving network and broadcast, which covers 50 hosts with only 12 wasted. Smaller masks such as /27 provide just 30 usable addresses, insufficient here, so /26 is the tightest fit satisfying the minimum-address constraint.
- ✗
255.255.255.224 (/27)
Why it's wrong here
A /27 mask yields 30 usable addresses, which cannot accommodate 50 hosts, so the requirement fails outright. It is tempting because /27 subnets suit small segments of up to 30 devices, such as point-to-point links or tiny departmental VLANs, where conserving address space matters more than host capacity.
- ✗
255.255.255.240 (/28)
Why it's wrong here
A /28 yields 16 addresses, only 14 usable after network and broadcast, so it cannot accommodate 50 hosts. It is tempting because /28 subnets suit small segments such as point-to-point links or tiny VLANs, where 14 usable addresses suffice. Here the requirement is 50 hosts, which needs at least a /26.
- ✗
255.255.255.128 (/25)
Why it's wrong here
A /25 mask yields 126 usable addresses, far exceeding the 50 hosts required, so it wastes 76 addresses. It is tempting because /25 is the natural choice when a subnet must be split into two equal halves, such as separating two departments of roughly 60 devices each.
Visual reference
About these practice questions
One of 975 original 200-901 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
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.