1)Major Network:192.20.15.0
2)CIDR /27 means every network contain 32 ip addresses.
3)Subnet Mask: 255.255.255.224
7th and 8th networks are not useful.
your are specified /27 means 32-27=5 every network contain 2^5 = 32 ip addresses so the answer is already in your given question .
if any further explanations please comment me.
What are the next two addresses? there are a total of 8 networks that can be...