lets say im connected to internet via broadband. My public IP is 188.8.131.52 . my question is if i connect to other pc in 184.108.40.206/24 network will they be able to monitor my data packets? if ping one of the system will they know?
Your public IP is owned by your ISP, which means that the other IPs in your network are also owned by your ISP. Even if the other IPs are not owned by the same ISP, the packets still travel over your ISP's network to reach the other network.
So, yes, they will see everything, because they are handling the traffic.
As schroeder said, as soon as your ISP handles your traffic they can see and inspect the data. Even if you encrypt your data (for example with https), the IP header cannot be encrypted because the networking equipment in the middle must know where to route your communications. In this second case your ISP can still see the source and destination IP address, even if they can't read your data. For that matter, any network that handles your data between you and the other machine will be able to see the source and destination IP address.
If both IP addresses actually belong to your ISP then it can be considerably difficult to hide from them the fact that you are communicating with another computer inside the same network. Even if you could set up multiple encrypted tunnels to completely obscure the source and destination IP addresses at both ends, they could still do a timing analysis to identify the fact that this other computer tends to receive data when your computer sends it.