Worksheet 10: Probability

Your name:

Your student ID number:

1. You win a dollar if you draw a red ball from the bag. Which of the two bags would you prefer to use? Why?

   • Bag A: 2 white balls and 3 red balls.

   • Bag B: 20 white balls and 30 red balls.

2. Suppose that each day you pick a random outfit by:

   • First picking one of 3 pairs of shoes.

   • Then picking one of 2 pairs of pants.

   What is the total number of possible outfits?

3. Suppose that each day you pick a random outfit by:

   • First picking one of 3 pairs of shoes.

   • Then picking one of 2 pairs of pants.

   • Then picking one of 4 shirts.

   What is the total number of possible outfits?

4. What is the probability that you wear flip-flops and one of the 2 long sleeved shirts?

5. Suppose that I randomly pick a student. What is the probability that they think we live in a simulation?

6. Suppose that I pick two different students. What is the probability that they both think we live in a simulation?

7. What is the probability that a randomly selected person has their birthday today (April 20)? What assumptions do you need to make?

8. What is the probability that a randomly chosen person has their birthday on the 20th day of the month?

9. Calculate the probabilities of the following events. What do you notice?

   • The die shows 1 or 2.

   • The die shows 3, 4, 5, or 6.