Problem Solving (PS) | If each participant of a chess tournament plays exactly one

You can also approach the question with combinations.

Let's say there are n people playing chess. You need to select 2 people from n people.

Number of ways of doing that is
nC2 = n!/(n-2)!2!

Reducing the above equation you get
n(n-1)/2 number of ways.

Now, n(n-1)/2
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