I have taken the PMP Exam Version 5.

There are 2 questions, but i forgotten the exact questions. But i try to quote example to the similar concept.

Q1) If 10 person were in this project, at a later stage 3 team member resign, 2 team member joined in, what will be the total communication channel ?

Q2) If 10 person where in this project, out of this 10 pple, 3 of them are part timers to the project, what will be the total communication channel ?

The formulae for calculating comm channels is n(n-1)/2