As far as I know Here subnet mask should be 255.255.255.128 instead of 200.1.1.128 and the two subnet id are 200.1.1.0 and 200.1.1.128 .To decide which subnet the packet belong we will bitwise AND subnet mask with the ip address of packet that will give us the Subnet address of packet. Correct me if I am wrong.

Thank You, Sir.

If in ques, we are given x bits for subnet bits in a network then we should substract 2 from 2^x for total no. of subnets possible or not ?

if we have 1-bit for subnet then we can divide a network in 2 parts.So, we loose 2*2=4 ip address.

if we have 2-bit for subnet then we can divide a network in 4 parts(b'cz 2^2).So, we loose 2*4=8 ip address.

if we have n-bit for subnet then we can divide a network in 2^n parts. So, we loose 2*(2^n) ip address.

And total no. of subnets possible =2^n

hope u understand.

yes we need to subtract for no of hosts for each subnet to get no of hosts

but in case of no of subnwts we have 2^x only

As far as I know Here subnet mask should be 255.255.255.128 instead of 200.1.1.128 and the two subnet id are 200.1.1.0 and 200.1.1.128 .To decide which subnet the packet belong we will bitwise AND subnet mask with the ip address of packet that will give us the Subnet address of packet. Correct me if I am wrong.