using the class c ip address 195.1.1.0 (class c means that only the last octet can be used for subnet and host addresses, or stated differently, the existing mask is 255.255.255.0). what would the new subnet mask be to establish 10 subnets each with a maximum 12 hosts on each subnet

Given a class C IP address

195.1.1.0

Existing mask is 255.255.255.0

We want to have 12 hosts on 10 subnets.

A class C address has 8 bits of the host which will give, n=8

2ⁿ - 2 = 254 hosts

Current mask = 255.255.255.0

Bits needs for 10 subnets

2ⁿ = 10, n = 4bits

n = 4 = 2⁴ = 16 possible subnets

Now, bit needed for 12host, n = 4bits

2⁴-2 = 14 possible host,

Total of 8 bits needed so therefore we can use as 4bits for the subnet.

So we could have

4 bit subnet and 4 bits hosts

11110000 = 240decimals

Final possible masks is

255.255.255.240