×
Time can be your best friend and your worst enemy depending on whether you use it or waste it.
--Your friends at LectureNotes
Close

Note for Permutation and Combination - PC by Placement Factory

  • Permutation and Combination - PC
  • Note
  • Quantitative Aptitude
  • Placement Preparation
  • 1042 Views
  • 67 Offline Downloads
  • Uploaded 1 year ago
0 User(s)
Download PDFOrder Printed Copy

Share it with your friends

Leave your Comments

Text from page-1

Permutations & Combinations Extension 1 Mathematics HSC Revision

Text from page-2

Multiplication Rule If one event can occur in m ways, a second event in n ways and a third event in r, then the three events can occur in m × n × r ways. Example Erin has 5 tops, 6 skirts and 4 caps from which to choose an outfit. In how many ways can she select one top, one skirt and one cap? Solution: Ways = 5 × 6 × 4

Text from page-3

Repetition of an Event If one event with n outcomes occurs r times with repetition allowed, then the number of ordered arrangements is nr Example 1 What is the number of arrangements if a die is rolled (a) 2 times ? 6×6 = 62 (b) 3 times ? 6×6×6 = 63 (b) r times ? 6 × 6 × 6 × ……. = 6r

Text from page-4

Repetition of an Event Example 2 (a) How many different car number plates are possible with 3 letters followed by 3 digits? Solution: 26 × 26 × 26 × 10 × 10 × 10 = 263 × 103 (b) How many of these number plates begin with ABC ? Solution: 1 × 1 × 1 × 10 × 10 × 10 = 103 (c) If a plate is chosen at random, what is the probability that it begins with ABC? Solution: 103 263 × 103 = 1 . 263

Lecture Notes