1.
X = {3, 4, 5, 6} and Y = {7, 8, 9, 10}. An element x is selected randomly from X and an element y is selected from Y. The value of x + y is then recorded.What is the probability that x + y is odd?
Correct Answer
D. 1 / 2
Explanation
Let E be the event that x + y is odd.
Using the possibility diagram, we can easily see that n(S) = 16 and n(E) = 8.
Therefore, P(E) = 8 / 16 = 1 / 2
2.
X = {3, 4, 5, 6} and Y = {7, 8, 9, 10}. An element x is selected randomly from X and an element y is selected from Y. The value of x + y is then recorded.What is the probability that x + y is even?
Correct Answer
D. 1 / 2
Explanation
Let F be the event that x + y is even.
Using the possibility diagram, we can easily see that n(S) = 16 and n(F) = 8.
Therefore, P(F) = 8 / 16 = 1 / 2
3.
X = {3, 4, 5, 6} and Y = {7, 8, 9, 10}. An element x is selected randomly from X and an element y is selected from Y. The value of xy is then recorded.What is the probability that xy is a multiple of 3?
Correct Answer
B. 5 / 8
Explanation
Let H be the event that xy is a multiple of 3.
Using the possibility diagram, we can easily see that n(S) = 16 and n(H) = 10.
Therefore, P(H) = 10 / 16 = 5 / 8
4.
X = {3, 4, 5, 6} and Y = {7, 8, 9, 10}. An element x is selected randomly from X and an element y is selected from Y. The value of xy is then recorded.What is the probability that xy is less than or equal to 30?
Correct Answer
D. 5 / 16
Explanation
Let H be the event that xy is less than or equal to 30 .
Using the possibility diagram, we can easily see that n(S) = 16 and n(I) = 5.
Therefore, P(I) = 5 / 16 = 5 / 16
5.
In a game, the player throws a coin and a regular die simultaneously. If the coin shows a head, the player's score is the score on the die. If the coin shows a tail, then the player's score is twice the score on the die. What is the probability that the score is even?
Correct Answer
C. 3 / 4
Explanation
Let E be the score is even.
Using the possibility diagram, we can easily see that n(S) = 12 and n(E) = 9.
Therefore, P(E) = 9 / 12 = 3 / 4
6.
In a game, the player throws a coin and a regular die simultaneously. If the coin shows a head, the player's score is the score on the die. If the coin shows a tail, then the player's score is twice the score on the die. What is the probability that the score is less than 6?
Correct Answer
B. 5 / 12
Explanation
Let F be the score is even.
Using the possibility diagram, we can easily see that n(S) = 12 and n(F) = 5.
Therefore, P(F) = 5 / 12
7.
A coin is flipped 4 times. What is the value of n(S)?
Correct Answer
D. 16
Explanation
Using a tree diagram, we can see that n(S) = 16.
8.
A coin is flipped 4 times. What is the probability of getting more than 2 heads?
Correct Answer
D. 5 / 16
Explanation
Let F be the event of getting more than 2 heads.
Using a tree diagram, we can see that n(F) = 5.
Therefore, P(F) = 5 / 16
9.
A coin is flipped 4 times. What is the probability of getting all 4 coins land on the same side?
Correct Answer
B. 1 / 8
Explanation
Let G be the event of all 4 coins land on the same side.
Using a tree diagram, we can see that n(G) = 2.
Note: 2 possible outcomes - All heads and all tails.
Therefore, P(G) = 2 / 16 = 1 / 8
10.
In a game, a player will have to throw a tetrahedral die and a coin at the same time. If he get a tail on the coin, the game will stop and he will receive the point based on the side facing down on the tetrahedral die. If he get a head on the coin, he will then throw the die again and he will receive the point based on the product of the 2 throws on the die. What are the number of different possible score a player can get?
Correct Answer
C. 9
Explanation
From the tree diagram, we can see that the possible scores that the player can score = {1, 2, 3, 4, 6, 8, 9, 12, 16}
Therefore, number of possible scores = 9.
11.
In a game, a player will have to throw a tetrahedral die and a coin at the same time. If he get a tail on the coin, the game will stop and he will receive the point based on the side facing down on the tetrahedral die. If he get a head on the coin, he will then throw the die again and he will receive the point based on the product of the 2 throws on the die. What is the value of n(S)?
Correct Answer
D. 20
Explanation
From the tree diagram, we can see that n(S) = 20.
12.
In a game, a player will have to throw a tetrahedral die and a coin at the same time. If he get a tail on the coin, the game will stop and he will receive the point based on the side facing down on the tetrahedral die. If he get a head on the coin, he will then throw the die again and he will receive the point based on the product of the 2 throws on the die. What is the probability of getting a score greater than 7?
Correct Answer
B. 3 / 10
Explanation
Let E be the event of getting a score greater than 7.
From the tree diagram, we can see that n(S) = 20 and n(E) = 6.
Therefore, P(E) = 6 / 20 = 3 / 10
13.
In a game, a player will have to throw a tetrahedral die and a coin at the same time. If he get a tail on the coin, the game will stop and he will receive the point based on the side facing down on the tetrahedral die. If he get a head on the coin, he will then throw the die again and he will receive the point based on the product of the 2 throws on the die. If the player can only wins if he/she get above a certain value. What is the value if the game only allows 2 / 5 of the players to win?
Correct Answer
B. 5
Explanation
Let F be the event that the player score more than 5 points.
From the tree diagram, we can see that n(S) = 20 and n(F)= 8.
Therefore, P(F) = 8 / 20 = 4 / 5