Answer
Combinations
Work Step by Step
A permutation from a group of items occurs when no item is used more than once and the
order of arrangement makes a difference.
(examples: arrangements, ordered lists, itineraries, schedules...)
A combination from a group of items occurs when no item is used more than once and the order
of items makes no difference.
(examples: committees, subsets, groups, ...)
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The actor selected first has no special role different to that of the second actor chosen,
at least not from the selection view.
A subset of 4 actors is chosen from the set of 20 actors.
The order of selection does not matter, we use combinations.
