8. C
The explanation that I came up with is that the network address is 150.50.0.0 which is originally assigned as a class B. So it has a default subnet mask of 255.255.0.0. Then you want to divide the network into seven different subnets and only the network address 255.255.240.0 is the one that provides enough networks because it will provide 14 subnets.
9. C
The explanation for this one that I came up with is that the network address 209.168.19.0 is originally assigned as a class C address because it has a default subnet mask of 255.255.255.0. You would need to divide this address space into four subnets and maximize the number of host addresses per subnet. You would do this by using 255.255.255.224 which would give you 6 subnets. Each subnet will have 30 host addresses available. The other answers to this question do not provide enough subnets and do not have 30 or more host addresses.
23. A
The ping uses ICMP echo packets to send to a host that reports if an echo reply is received or not. If indeed the echo reply is received then the host is working and operating correctly on the network. The other answers to this question are not correct because ARP resolves MAC addresses to IP addresses. This is done through the use of broadcasts which are not publicized across the Internet. DNS is used to resolve a domain name to an IP address and it does not send communication directly to a network host. WINS does not support the most Unix machines and provides windows to a computer name which doesn’t resolve in an enterprise and is not used on the internet.
29. B
Since the network address is a Class B address, you would have to divide the address into three subnets which will minimize waste of IP addresses. The 255.255.255.0 subnet mask is the only answer that provides enough space to support 175 hosts that are providing more than 3 subnet