If my ip is 192.168.1.151 and subnet is 255.255.255.0 so what is my default Gateway?

depends up the IP of  your gateway , it may be any thing , but generally we put first or last ip of your network  ie 192.168.1.1 or 192.1681. 254

192.168.1.1 THE GATEWAY ADRESS IS 

Default Gateway is 192.168.1.1

Default gateway is depend upon netowork policy, however in normal routine it can be 192.168.1.1 or 192.168.1.254

the Default Dateway is 192.168.1.1

any IP from 192.168.1.1 to 192.168.1.254 except 192.168.1.151.

Br

Feterzon

Anything you can use between 192.168.1.1 to 192.168.1.254

192.168.1.1 default gateway192.168.1.0 network address

Default gateway can be between 192.168.1.1 to 192.168.1.254 except 192.168.1.151 

Default gateway should be 192.168.1.x....The x can be determined by the network administrator and it can be between 1-254.