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Cogito

Integrated Math 2 · Chapter 8 · Lesson 1

Practice Worksheet

Probability of Compound Events

Combining two events.

12 problems · about 21 minutes · S-CP.A.1, S-CP.B.7

NameDate

Figure — use these to answer the problems

Change the counts. Each probability is a category over the total of all of them.
Red4
Blue6
Red4
Blue6
Figure 1

Warm Up

Straightforward practice. Get the method working first.

5 problems

  1. P(A) = 0.5, P(B) = 0.3, independent. What is P(A and B)?

    Answer

  2. Why does the or rule subtract the overlap?

    • It would otherwise be counted in both terms.
    • To make the answer smaller.

  3. P(A) = 0.4, P(B) = 0.5, independent. P(A and B)?

    Answer

  4. P(A) = 0.3, P(B) = 0.2, mutually exclusive. P(A or B)?

    Answer

  5. P(A) = 0.6. What is P(not A)?

    Answer

Build It Up

The same ideas with more to keep track of.

3 problems

  1. P(A) = 0.5, P(B) = 0.4, P(A and B) = 0.2. P(A or B)?

    Answer

  2. Two dice. Probability both show six, to three decimal places?

    Answer

  3. A bag has 4 red and 6 blue. Probability of red, as a decimal?

    Answer

Stretch Yourself

Mixed problems. Work out what kind of question it is before you start.

4 problems

  1. Sort each pair by whether the events are independent.

    Write each item under the heading it belongs to: Two separate coin tosses · Rolling a die twice · Two draws from a bag without replacement · Drawing a red card and drawing a spade on one card

    Independent

    Not independent

  2. P(A) = 0.25, P(B) = 0.8, independent. P(A and B)?

    Answer

  3. The Two Coins

    Two fair coins. Probability both are heads, as a decimal?

    Answer

  4. The Complement

    Three fair coins. Probability of at least one head, as a decimal?

    Answer