Finite Mathematics : Finite Mathematics

Study concepts, example questions & explanations for Finite Mathematics

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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.

Possible Answers:

False

True

Correct answer:

True

Explanation:

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?

Possible Answers:

Permutation

Combination

Correct answer:

Combination

Explanation:

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 ?

Possible Answers:

Correct answer:

Explanation:

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.

Possible Answers:

False

True

The statement has no truth value.

Correct answer:

True

Explanation:

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

Possible Answers:

(1), (2), and (3)

(1) and (3) only

(1) and (2) only

(2) and (3) only

(1) only

Correct answer:

(1), (2), and (3)

Explanation:

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?

Possible Answers:

Correct answer:

Explanation:

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?

Possible Answers:

17 to 8

42 to 17

25 to 17

42 to 25

25 to 8

Correct answer:

17 to 8

Explanation:

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?

Possible Answers:

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.

Correct answer:

The value of the game is $1.92 in Jack's favor.

Explanation:

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?

Possible Answers:

Correct answer:

Explanation:

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.

Possible Answers:

True

Fallse

Correct answer:

True

Explanation:

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.

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