2.2 The Fundamental Counting Principle

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2.2 The Fundamental Counting Principle

Learning Goal

I am learning to use the fundamental counting principle for counting and to solve problems

Investigate Determining the Number of Outcomes

1

2 a) Roll one die and flip a coin. Make a list or a diagram to illustrate all the possible outcomes. b) How many outcomes are possible?

Roll one die, flip a coin, and spin a spinner with four equal sections. Without making a list or diagram, determine how many outcomes are possible. Describe your method.

3 Randomly select a number between 1 and 100, and a letter from the alphabet. How many outcomes are possible? How did you know this without counting all the outcomes?

4 Events A and B are independent. Event A has 𝑚 outcomes. Event B has 𝑛 outcomes. How many outcomes are possible, in total, if both events occur together?

5 Explain why your method in step 4 works.

Fundamental Counting Principle

If one event can occur in 𝑚 ways and a second event can occur in 𝑛 ways, then together they can occur in 𝑚 × 𝑛 ways.

Example 1 Counting Repeated Independent Trials

You flip a fair coin. How many outcomes are possible with a) two flips? b) three flips?

Example 2 Counting Repeated Trials Without Replacement

Two letter tiles are chosen from full alphabet without replacement.

How many possible outcomes are there?

Reflect

R1. Evan reasons that when rolling two 10-sided dice, since each has 10 outcome, there are 10

+ 10 = 20 outcomes in total. Is he right or wrong? Explain.

R2. If a tree diagram has 3 levels with 𝑝 outcomes at the first level, 𝑞 outcomes at the second level and 𝑟 outcomes at the third level, how many outcomes are there in total?

Homework

p. 73 #1 – 10, 13 – 16

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