Difficulty: Medium
Correct Answer: 255.255.255.192
Explanation:
Introduction / Context:Subnetting a class C network (default /24) to obtain a required number of subnets while maximizing hosts per subnet is a core IP addressing skill. Here we need four subnets with as many hosts as possible per subnet on 192.168.10.0.
Given Data / Assumptions:
Concept / Approach:Number of subnets with borrowed bits: subnets = 2^n. Number of hosts per subnet = 2^(host_bits) - 2. For a class C (/24), there are 8 host bits before borrowing. Borrow as few bits as necessary to reach 4 subnets to keep more host bits (thus maximizing hosts per subnet).
Step-by-Step Solution:
1) Need 4 subnets -> n such that 2^n = 4 -> n = 2 bits borrowed. 2) New prefix = /24 + 2 = /26. 3) Hosts per /26 = 2^(8 - 2) - 2 = 2^6 - 2 = 64 - 2 = 62 hosts. 4) /26 corresponds to mask 255.255.255.192.Verification / Alternative check:Subnets would start at 192.168.10.0, .64, .128, .192 with broadcast addresses .63, .127, .191, .255 respectively, each supporting 62 usable host IPs. This satisfies the requirement of exactly 4 subnets with the maximum host count per subnet.
Why Other Options Are Wrong:
Common Pitfalls:Borrowing more bits than necessary (reduces hosts); forgetting to subtract 2 for network and broadcast; mixing up /26 vs /27 boundaries.
Final Answer:255.255.255.192
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