Ratios, Rates and Percents Lesson 16 Ratios, Rates and Percents Introduction to Probability

Warm-Up Write each percent as a fraction in simplest form and a decimal. 1. 35% 2. 20%   Write each fraction or decimal as a percent 3. 4. 0.78   Jimmy bought a new television on sale for 30% off the original price. The original price was $1,200. How much was the discount on the television?

Introduction to Probability Target: Recognize probabilities that are unlikely and likely. Express probabilities as fractions, decimals and percents.

Vocabulary Probability: The measure of how likely it is something will occur.

Example 1 Determine whether each event is impossible, unlikely, equally likely, likely, or certain. a. A card thrown on the floor lands face up. Equally likely – only two options, no one is more likely than the other. b. You roll a 2 on a regular number cube. Unlikely – there are six numbers and 2 is only one of them. c. You are older now than when you were born. Certain – Everyone is older now than when they were born.

Example 2 Dexter’s teacher said there was an 80% chance of getting math homework this weekend. Write this probability as a simplified fraction and a decimal. As a fraction: As a decimal: An 80% chance of math homework is the same as an 0.8 chance of homework or a chance of homework.

Example 3 Felipe asked 50 students Action: 40% of 50 which type of movie they 0.4 × 50 = 20 people most preferred. Forty Drama: of 50 percent chose action movies, chose drama and 0.5 chose comedy. How many of the students chose Comedy: 0.5 of 50 each type of movie? 0.5 × 50 = 25 people

Exit Problems Determine whether each probability is impossible, unlikely, equally likely, likely, or certain. You roll a 1, 2, 3, 4 or 5 on a number cube. You toss a coin and it lands “heads”. You pick a blue sock out of a drawer filled with white and black socks. There is a 0.6 chance that Tabitha will choose the winning card. Write this probability as a percent and a simplified fraction.

Communication Prompt Decide whether you prefer to work with probabilities as percents, decimals, or simplified fractions. Why did you choose percents, decimals or simplified fractions? If you do not have a preference, explain why not.