The subnet mask would be | GATE CS

GATE CSIT 2005 : 

An organization has a class B network and wishes to form subnets for 64 departments. The subnet mask would be:
A) 255.255.0.0
B) 255.255.64.0
C) 255.255.128.0
D) 255.255.252.0
Solution:

Class

Address Range

Subnet mas

Example

Leading bits

Max number of networks

A

1 to 126

255.0.0.0

1.1.1.1

8

128

B

128 to 191

255.255.0.0

128.1.1.1

16

16384

C

192 to 223

255.255.255.0

192.1.11.

24

2097157

D

224 to 239

E

240 to 254