Permutations

Probability · Axiom Academy

Counting arrangements when order matters A permutation is an ordered arrangement of objects. Different orders create different permutations. Watch how we generate all permutations of 3 letters: To find the number of ways to arrange r objects chosen from n distinct objects, we use the permutation formula. Let's derive this formula step by step: 3. Worked Example: Race Podium In a race with 8 runners, how many different ways can the gold, silver, and bronze medals be awarded? Let's visualize how we fill each podium position: 4. Permutations with Repetition When we can repeat choices (like digits in a PIN), we use a different formula. Compare permutations with and without repetition:

This is the written version of the interactive lesson above. See the full Probability course.