1. Lesson 2

1.7. Explore 5

Mathematics 30-3 Module 1

Module 1: Probability

 

This is a photograph of a beach in Hawaii on a sunny day.

Photodisc/Thinkstock

Self-Check 3

 

You have been offered the opportunity to complete an online customer satisfaction survey for Home Renos Supply Depot. All survey entries receive a prize. After submitting your comments, you are entered into a draw to determine your prize. The grand prize is an all-inclusive one-week paid trip to Hawaii. Ten thousand (10 000) surveys are entered into the draw, and the prizes are distributed as follows:

 

Prize

Number of Prizes of This Type

5% off your next purchase

7922

10% off your next purchase over $250

1577

30% off your next purchase over $500

500

All-inclusive one-week paid trip for two to Hawaii

1

 

Elia and Erryn have filled in satisfaction surveys and are discussing the probability of winning the grand prize. Elia says she thinks she has a 1 in 4 chance of going to Hawaii because there are four prizes available and she will win one of them. Erryn says that sounds too good to be true.

  1. Which girl do you agree with? Explain. Answer
  2. What is the formula for the probability of winning a certain prize? Answer
  3. What is the probability of winning a prize of 30% off your next purchase over $500? Answer
  4. What is the probability of winning a prize other than 5% off your next purchase? Answer
  5. If you checked the prizes of 500 people, how many do you expect received the 5% discount? Answer

In Self-Check 3 you may have noticed that, in fact, there is not a 1 in 4 chance of winning the trip to Hawaii. Why? Because the four options do not have equal probabilities.

 

The probability of the individual events must be equal to use the formula

 

You also saw that the probability of an event that must happen is 1, and the probability of an event that cannot happen is 0.

 

The diagrams illustrate these ideas.

 

This diagram shows a circular spinner with red, green, and blue sections. The red section is approximately 8% of the area, the green section is approximately 22% of the area, and the blue section is approximately 70% of the area.

 

This diagram shows a circular spinner that is entirely blue.

 

Self-Check 4

 

You have a bag with 9 red marbles, 6 blue marbles, and 5 green marbles. A marble is selected and then put back in the bag. Answer each of the following questions as a fraction in lowest terms, as a decimal, and as a percentage. What is the probability of randomly selecting the following colours of marbles?

  1. a green marble Answer
  2. a red or blue marble Answer
  3. a black marble Answer
  4. a non-green marble Answer
  5. a pink marble Answer
  6. Explain why the probability of selecting a red marble is not Answer
Self-Check 5


textbook

Answer “Build Your Skills” questions 4 and 8 on pages 163 and164 of the textbook. Answer

 

 



glossary

Add theoretical probability to your copy of Glossary Terms.