All Finite Mathematics Resources
Example Questions
Example Question #81 : Finite Mathematics
Consider the logical proposition:
"William Shakespeare is dead."
True or false: The proposition "William Shakespeare is alive" is the negation of that statement.
False
True
True
The negation of a proposition is the proposition "Not ," or, "It is not true that ."
The negation of "William Shakespeare is dead" is "It is not true that William Shakespeare is dead," or, simply, "William Shakespeare is alive."
Example Question #42 : Logic, Sets, And Counting
In order to win the grand prize in a lottery, the six numbers that come up must match the six numbers you chose; the order in which they come up need not be the same as the order on your ticket.
Is this is an example of a permutation or a combination?
Permutation
Combination
Combination
A combination is defined as an unordered subset of a set; a permutation is an ordered subset. The key to answering this question is the phrase " the order...need not be the same." This is an indication that this is a combination.
Example Question #42 : Logic, Sets, And Counting
Try without a calculator:
Which of the following is equal to ?
For any whole numbers , where ,
Setting :
.
Example Question #82 : Finite Mathematics
Consider the conditional statement
"If , then every duck is a bird."
Give the truth value of this statement.
False
True
The statement has no truth value.
True
This conditional statement has a false antecedent , so, by the principles of logic, it is considered to have truth value "true." The truth value of the consequent is irrelevant.
Example Question #1 : Probability
A card is drawn at random from a standard deck of 52 cards (the joker is not included), and its rank and suit are recorded.
Which of the following changes both the probability of drawing a black card and that of drawing an ace?
1) Replacing the ace of spades with the joker
2) Adding the joker
3) Removing the ace of spades
(1), (2), and (3)
(1) and (3) only
(1) and (2) only
(2) and (3) only
(1) only
(1), (2), and (3)
If a card is drawn at random from a standard deck of 52, the probability of drawing one of the 26 black cards is ; the probability of drawing an ace is . Now, examine each of the three scenarios.
(1) If the ace of spades is replaced with the joker, this leaves 25 black cards and 3 aces out of a total of 52 cards. The probability of drawing one of the 25 black cards is ; the probability of drawing an ace is .
(2) If the joker is added, there are still 26 black cards and 4 aces, but the deck now has 53 cards. The probability of drawing one of the 25 black cards is ; the probability of drawing an ace is .
(3) If the ace of spades is removed, this leaves 25 black cards and 3 aces out of a total of 51 cards. The probability of drawing one of the 25 black cards is ; the probability of drawing an ace is .
In all three cases, both probabilities have changed.
Example Question #82 : Finite Mathematics
The odds in favor of an event occurring are 17 to 4. To the nearest hundredth, what is the probability of the event happening?
If the odds in favor of an event are to , the probability of that event is . Setting and , the probability of the event is
.
Example Question #1 : Probability
The probability of an event is . What are the odds in favor of the event?
17 to 8
42 to 17
25 to 17
42 to 25
25 to 8
17 to 8
The odds in favor of an event are equal to the ratio of the probability of the event to that of the opposite event. Therefore, we want to determine :
,
or 17 to 8 in favor.
Example Question #1 : Probability
Jack and Jill agree to a game. A card is drawn at random from a standard deck of 52 (no joker). If the card is a face card (king, jack, queen) or a ten, Jack plays Jill $50. If the card is anything else, Jill pays Jack $25.
Which of the following is true of the game?
The value of the game is $1.92 in Jack's favor.
The game is fair.
The value of the game is $7.69 in Jill's favor.
The value of the game is $1.92 in Jill's favor.
The value of the game is $7.69 in Jack's favor.
The value of the game is $1.92 in Jack's favor.
The fairness or unfairness of the game is a function of the expected value, which can be calculated by multiplying the probability of each outcome by its value, and adding the products.
We will examine the value of the game to Jack; a positive value indicates a gain to Jack, and a negative value indicates a gain to Jill.
Since only ranks matter in this game, there are thirteen equiprobable outcomes. Four are favorable to Jill, and the other nine are favorable to Jack. There are two events, a win for Jill and a win for Jack, which we will call and , respectively. Their probabilities and their values to Jack are:
: A king, queen, jack, or ten is drawn, and Jill wins.
Probability:
Value to Jack:
: A card of any of the other nine ranks is drawn, and Jack wins:
Probability:
Value to Jack:
The expected value of one play of the game to Jack is
in Jack's favor.
Example Question #2 : Probability
The twelve face cards (kings, queens, jacks) are separated from a standard deck of 52 cards. Two cards are selected at random from the twelve, without replacement. What is the probability that both cards will be kings?
Two cards are drawn from the deck without regard to order, so the sample space is the set of all combinations of two cards from a set of twelve. The size of this sample space is
The event is the set of all combinations of two cards from the set of four kings. The size of this event space is
The probability of the event is
Example Question #3 : Probability
Jack and Jill agree to a game. A card is drawn at random from a standard deck of 52. If the card is a spade, Jack plays Jill $75. If the card is anything else, Jill pays Jack $25.
True or false: This is an example of a fair game.
True
Fallse
True
The fairness or unfairness of the game is a function of the expected value, which can be calculated by multiplying the probability of each outcome by its value, and adding the products.
We will examine the value of the game to Jack; a positive value indicates a gain to Jack, and a negative value indicates a gain to Jill.
Since only suits matter in this game, there are four equiprobable outcomes. One is favorable to Jill, and the other three are favorable to Jack. There are two events, a win for Jill and a win for Jack, which we will call and , respectively. Their probabilities and their values to Jack are:
: A spade is drawn, and Jill wins.
Probability:
Value to Jack:
: A card of any of the other three suits is drawn, and Jack wins:
Probability:
Value to Jack:
The expected value of one play of the game to Jack is
The game is fair.