"What's the problem with using 255.255.255.247 as a subnet mask if you want to make a LAN subnet with 12 hosts?" (5 word answer)
My response would be: Discontiguous subnet masks were allowed in the pre-CIDR era. If you so desire, give me about 2 hours since I do not have a scientific calculator handy; and I will get back to you with the complete-list.
Definitely not 5 words as required from the HR stand point. So I get disqualified again!
Hehehe. Ok. So if this was 1986 then the answer would be: No Hosts on the Network. There is only 1 host bit, and both available addresses would be reserved for the directed-broadcast and subnet-broadcast address respectively, leaving no space for an actual host, let alone 12 of them. --- () ascii ribbon campaign against html e-mail /\ www.asciiribbon.org