Counting Principle

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Counting Principle

• Chapter 10 Lesson 4

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• Suppose that you and a friend are making
  sandwiches for lunch. You can use either chicken
  or roast beef. For bread you choices are pita,
  wheat, or pumpernickel. How many different
  sandwiches can you make?
• Chicken on Pita, Wheat, or Pumpernickel
• Beef on Pita, Wheat, or Pumpernickel
• There are 6 different sandwiches

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Counting Principal

• Find the number of possible outcomes if an event
  by multiplying the number of outcomes at each
  stage of event.

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Example 1

• Benita needs a computer system for her home
  office. She must choose which computer, monitor,
  and printer to buy. The table shows
  possibilities from which she can choose. From
  how many different configurations can she choose?
  
• Brands of computers Plum, Ideal, Sunflower, AA
  Tech
• Size of monitor 14. 17, 21
• Type of printer inkjet, laser
• Computer x Monitor x Printer number of
  configurations possible
• 4 x 3 x 2
  24 possible configurations

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Example 2

• In a game, a player tosses a number cube and
  chooses one if 26 alphabet cards. Using the
  counting principle, find P (Prime number, T or
  Q)?
• First find the number of possible outcomes.
• 6 x 26 156
• Then find the number of favorable outcomes.
• Prime (3) x Letters (2) 6
• P (Prime number, T or Q) 6/156 1/26