CCNA question

[gporter]

Tryinh to figure out how to resolve these. And the steps to do so.

Given the IP address 192.168.21.12 from the class C address range your network needs addresses for 28 small offices. Each office uses its own subnet. The network designs specify that you configure for 5 bits of subnetting when you configure the Cisco IOS software. Which subnet mask should you use?

A. 255.255.0.28
B. 255.255.255.0
C. 255.255.255.28
D. 255.255.255.248
E. 255.255.255.252


Which network mask should you place on a class C address to accommodate a user requirement for five networks with a maximum of 17 hosts on each network?
A. 255.255.255.192
B. 255.255.255.224
C. 255.255.255.240
D. 255.255.255.248

 

[CCIEWANNABE]

Link:
thread581-265755 review this link

IP Address : 192.168.21.12
Address Class : C
Network Address : 192.168.21.0

Subnet Address : 192.168.21.8
Subnet Mask : 255.255.255.248
Subnet bit mask : 110nnnnn.nnnnnnnn.nnnnnnnn.nnnnn[/red]hhh
Subnet Bits : 29 nnnnn[/red]
Host Bits : 3
Possible Number of Subnets : 32
Hosts per Subnet : 6

Question two:

IP Address : 192.168.21.12
Address Class : C
Network Address : 192.168.21.0

Subnet Address : 192.168.21.0
Subnet Mask : 255.255.255.224
Subnet bit mask : 110nnnnn.nnnnnnnn.nnnnnnnn.nnnhhhhh[/red]
Subnet Bits : 27
Host Bits : 5 hhhhh[/red]

Possible Number of Subnets : 8
Hosts per Subnet : 30



Route once; switch many