I have below query which marked in red. My query is related to Network Subnet Mask

Case

Imagine that an organization is assigned the block of addresses defined by 99.216.0.0/13. The organization initially must support 100 hosts on the first subnet, and 13 hosts on the second subnet. Using VLSMs, it creates the network identifiers as follows.

First Subnet: 01100011 11011000 00000000 0

Second Subnet: 01100011 11011000 00000000 1000

After some time passes, the organization needs a third subnet that supports 100 hosts, and a fourth subnet that supports 29 hosts, which the organization allocates. The four subnets network identifiers are as follows:

First Subnet: 01100011 11011000 00000000 0

Second Subnet: 01100011 11011000 00000000 1000

Third Subnet: 01100011 11011000 00000001 0

Fourth Subnet: 01100011 11011000 00000000 101

1. How many bits are used by the subnet identifier of the fourth subnet?

Answer: 14 bits are used.

My question: How 14 bits are derived for 4^th Subnet. I am not getting this properly.

My question: For this below case, how many bits are used by each subnet?

Imagine that an organization is assigned the IP address block defined by

237.118.0.0/15, and that the organization needs one subnet that supports 400 hosts,

and another that supports 77 hosts. The organization allocates the subnets network

identifiers as follows:

First subnet: 11101101 01110110 0000000

Second subnet: 11101101 01110110 00000010 0

Answer: 1 bit is used.

My question: How 1 bit is derived. Is this the correct answer?