Hello Chaminda
You are correct. The output should actually read:
Link connected to: a Stub Network
(Link ID) Network/subnet number: 10.0.35.0
(Link Data) Network Mask: 255.255.255.0
Number of TOS metrics: 0
TOS 0 Metrics: 17
where the (Link ID) Network/subnet number should be 10.0.35.0 and not 10.0.15.0.
I will let Rene know to change that.
The /24 in the label of that DR just indicates that this DR is performing its function for a point to point link, that is, a single /24 subnet. This is stated later on in the lesson as shown:
I hope this has been helpful!
Laz