You are working with a network engineer to design a network for the new Campus. He provided the following details:
The IP address is 195.240.37.43
The subnet mask is 255.255.255.224

You have been tasked to:
1. Find the Prefix length
2. Find the Class of the address

(A) Prefix length = 27 | Class = C
(B) Prefix length = 20 | Class = B
(C) Prefix length = 15 | Class = C
(D) Prefix length = 30 | Class = A

Prefix length = 27 | Class = C is the correct answer. The Prefix Length can be found once you convert the mask to binary and count the 1s.

In this case, the subnet mask 255.255.255.224 in binary is 11111111.11111111.11111111.11100000.
Count the number of the 1s to find the prefix length.
Prefix Length: /27.
The address 195.240.37.43 is a Class C.
The range of Class C public IP Networks is: 192.0.0.0 – 223.255.255.0
The number Network bits for Class C address is 24 bits.