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Lesson 33: Finding the Probability of Independent and Dependent Events — Practice Questions

  1. 1. You roll a standard six-sided die and then flip a fair coin. Which statement best describes these two events?

    • A. The events are dependent because they happen in sequence.
    • B. The events are independent because the outcome of the die roll does not affect the outcome of the coin flip.
    • C. The events are dependent because the total number of outcomes is 12.
    • D. The events are independent because they both involve chance.
  2. 2. A drawer contains 5 black socks and 7 white socks. You randomly pick one sock, do not replace it, and then pick a second. What is the probability both socks are black? Express your answer as a simplified fraction. ___

  3. 3. A bag contains 3 green balls and 5 yellow balls. You draw a ball, replace it, and then draw a second ball. What is the probability that you draw a green ball both times? Express your answer as a fraction. ___

  4. 4. A bag has 4 red and 6 blue marbles. You draw one marble, do not replace it, then draw a second. What is the probability the first is red and the second is blue? Express your answer as a simplified fraction. ___

  5. 5. In an experiment where you draw two cards from a deck without replacement, why are the events considered dependent?

    • A. Because the total number of cards and the number of specific cards both decrease after the first draw.
    • B. Because the color of the first card drawn is unknown.
    • C. Because the second card drawn is always different from the first.
    • D. Because card drawing is always a dependent event.
  6. 6. A bag contains 8 red and 4 green marbles. Two marbles are drawn without replacement. What is the probability that both marbles drawn are red? Express as a simplified fraction: ___.

  7. 7. A class has 12 boys and 10 girls. If two students are randomly selected without replacement, what is the probability that the first is a girl and the second is a boy?

    • A. $\frac{60}{242}$
    • B. $\frac{20}{77}$
    • C. $\frac{132}{484}$
    • D. $\frac{10}{21}$
  8. 8. From a standard 52-card deck, two cards are drawn without replacement. What is the probability of drawing a King and then a Queen? Express your answer as a simplified fraction: ___.

  9. 9. A drawer contains 10 blue socks and 6 black socks. If two socks are drawn randomly without replacement, what is the probability that both socks are black?

    • A. $\frac{1}{8}$
    • B. $\frac{9}{64}$
    • C. $\frac{3}{20}$
    • D. $\frac{1}{10}$
  10. 10. Which statement best describes why drawing two items from a bag without replacement are considered dependent events?

    • A. The probability of the second event is always smaller than the first.
    • B. The outcome of the first draw affects the probabilities for the second draw.
    • C. The items are identical.
    • D. The probability is found by adding the individual probabilities.