~ 8.8 ~

Learning Targets

• I can use a simulation to estimate the probability of a multi-step event.

Sometimes we need a systematic way to count the number of outcomes that are possible in a given situation. For example, suppose there are 3 people (A, B, and C) who want to run for the president of a club and 4 different people (1, 2, 3, and 4) who want to run for vice president of the club. We can use a tree, a table, or an ordered list to count how many different combinations are possible for a president to be paired with a vice president.

With a tree, we can start with a branch for each of the people who want to be president. Then for each possible president, we add a branch for each possible vice president, for a total of 3 • 4 = 12 possible pairs. We can also start by counting vice presidents first and then adding a branch for each possible president, for a total of 3 • 4 = 12 possible pairs.

So does this ordered list:

A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3, C4

How many different meals are possible if each meal includes one main course, one side dish, and one drink?

Consider the experiment: Flip a coin, and then roll a number cube.

Elena, Kiran, and Priya each use a different method for finding the sample space of this experiment.

• 1. Compare the three methods. What is the same about each method? What is different?

  2. Which method do you prefer for this situation?

  3. Find the sample space for each of these experiments using any method. Make sure you list every possible outcome without repeating any.

     1. • Flip a dime, then flip a nickel, and then flip a penny. Record whether each lands heads or tails up.

        • Han’s closet has: a blue shirt, a gray shirt, a white shirt, blue pants, khaki pants, and black pants. He must select one shirt and one pair of pants to wear for the day.

        • Spin a color, and then spin a number.

        • Spin the hour hand on an analog clock, and then choose a.m. or p.m.

8.3 How Many Sandwiches?

1. A submarine sandwich shop makes sandwiches with one kind of bread, one protein, one choice of cheese, and two vegetables. How many different sandwiches are possible? Explain your reasoning.

   • Breads: Italian, white, wheat

   • Proteins: Tuna, ham, turkey, beans

   • Cheese: Provolone, Swiss, American, none

   • Vegetables: Lettuce, tomatoes, peppers, onions, pickles

2. Andre knows he wants a sandwich that has ham, lettuce, and tomatoes on it. He doesn’t care about the type of bread or cheese. How many of the different sandwiches would make Andre happy?

3. If a sandwich is made by randomly choosing each of the options, what is the probability it will be a sandwich that Andre would be happy with?

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