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Permutations

CONCEPTS

Equation

• Number of permutations = Number of Event A * (Number of Event B – 1) * (Number of Event C – 1)


Tips

• The word, combination, is typically in the question


Definitions

• Permutations: The number of possible arrangements where order does matter

PRACTICE PROBLEMS

Question 1 A reservation number is composed of 5 digits. The digits can be any number from 0 - 9. The digits may NOT repeat. How many possible 5 digit reservations numbers are there?


-- Answer -- 10 * 9 * 8 * 7 * 6



Question 2 Given 4 racers, how many arrangements are there?


-- Answer -- 24

4 * 3 * 2 * 1 = 24

The 1st pick will have 4 racers and 1 will be selected. The 2nd pick will have 3 racers and 1 will be selected. The 3rd pick will have 2 racers and 1 will be selected

ACT PRACTICE PROBLEMS

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