Reasoning
Handshakes
Calculate pairwise handshakes when each pair meets once.
Number of Handshakes = n(n - 1) / 2
Formula Explanation
Each handshake corresponds to one unique pair among n people.
Variables Explained
n = Number of people.
Solved Example
How many handshakes occur among 8 people if each pair shakes hands once?
8 × 7 / 2 = 28 handshakes.