Probability Unit Test ( ANSWERS)
1. A bag contains 6 red marbles, 4 blue marbles, and 5 green marbles. If a marble is randomly selected from the bag, what is the probability that it is blue?
Answer: P(blue) = 4/15
2. A standard deck of cards contains 52 cards, with 4 suits (hearts, diamonds, clubs, spades), and 13 cards per suit. If a card is randomly selected from the deck, what is the probability that it is a heart?
Answer: P(heart) = 13/52 = 1/4
3. A coin is flipped 3 times. What is the probability of getting exactly 2 heads?
Answer: P(2 heads) = (3 choose 2) * (1/2)^2 * (1/2)^1 = 3/8
4. A box contains 10 white balls and 5 black balls. If 2 balls are randomly selected from the box without replacement, what is the probability that both balls are white?
Answer: P(both white) = (10/15) * (9/14) = 3/7
5. A spinner is divided into 8 equal sections, numbered 1 to 8. If the spinner is spun once, what is the probability of landing on an even number?
Answer: P(even number) = 4/8 = 1/2
6. A bag contains 3 red marbles and 7 blue marbles. If a marble is randomly selected from the bag, what is the probability that it is not red?
Answer: P(not red) = 7/10
7. A card is randomly selected from a standard deck of cards. What is the probability that it is a face card (jack, queen, or king)?
Answer: P(face card) = 12/52 = 3/13
8. A bowl contains 5 apples, 3 oranges, and 2 bananas. If a piece of fruit is randomly selected from the bowl, what is the probability that it is an orange?
Answer: P(orange) = 3/10
9. A box contains 4 red marbles and 6 green marbles. If 2 marbles are randomly selected from the box with replacement, what is the probability that both marbles are red?
Answer: P(both red) = (4/10) * (4/10) = 16/100 = 4/25
10. A fair 6-sided die is rolled. What is the probability of rolling a number greater than 4?
Answer: P(number > 4) = 2/6 = 1/3