In a full mesh network topology containing 13 nodes, how many physical channels exist between all of the nodes?

In a full mesh network topology containing 13 nodes, how many physical channels exist between all of the nodes?

• 84
• 78
• 64
• 56 

EXPLANATION

 In a mesh topology, each node has a dedicated point-to-point link to every other nodes.
If the number of nodes in a fully mesh network is n, then the total number of physical channels to link all nodes are n(n-1)/2.
Substituting 13 for n, the result is 78.