University:
University of North Georgia
Course:
MATH 1001 | Quantitative Skills and Reasoning
Academic year:

2020
Views:

336

Pages:

1
Author:

Kyuwon J.

Definition: If n is a positive integer, the notation n! (Read “n factorial”) is the product of all positive integers from n down through 1 EXAMPLE: 1! = 1 2! = 2x1=2 3!= 3x2x1=6 4!= 4x3x2x1=24 5!= 5x4x3x2x1=120 6!=6x5x4x3x2x1=720 A Formula for Permutations ● 13 batters ● A batting order having 9 players 13 x 12 x 11 x 10 x 9 x 8 x 7 x 6 x 5 = 259,459,200 *** The number of possible permutations of r items are taken from n items is: nPr= n!/ (n-r)! EXAMPLE: Using the Formula for Permutations: You and 19 of your friends have decided to form a business. The group needs to choose three officers- a CEO, an operating manager, and a treasurer. In how many ways can those offices be filled. Solution: Your group is choosing r=3 officers from a group of n=20 people. The order matters because each officer has different responsibilities. nPr = 20P3 = 20!/(20-3)! = 20!/17! = 20x19x18x17/17 (cross out both 17s) = 20x19x18=6840 Permutations of Duplicate Items ● SET——> 3! Or 6 SET STE EST ETS TES TSE - What if ANA ANA AAN NAA NAA ANA AAN ANA AAN NAA

Quantitative Reasoning Chapter 1

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