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A,B,C, and D are all answer choices A common way for two people to settle a friv

ID: 3201519 • Letter: A

Question

A,B,C, and D are all answer choices

A common way for two people to settle a frivolous dispute is to
play a game of rock-paper-scissors. In this game, each person
simultaneously displays a hand signal to indicate a rock, a piece
of paper, or a pair of scissors. Rock beats scissors, scissors
beats paper, and paper beats rock. If both players select the
same hand signal, the game results in a tie.

Two roommates, roommate A and roommate B, are expecting
company and are arguing over who should have to wash the
dishes before the company arrives. Roommate A suggests a
game of rock-paper-scissors to settle the dispute.

Consider the game of rock-paper-scissors to be an experiment. In the long run, roommate A chooses rock 36% of the time, and
roommate B chooses rock 22% of the time; roommate A selects paper 32% of the time, and roommate B selects paper 25% of
the time; roommate A chooses scissors 32% of the time, and roommate B chooses scissors 53% of the time. (These choices are
made randomly and independently of each other.)

The probabilities were assigned using the

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Define event A as the event that roommate A wins the game and thus does not have to wash the dishes.

What is P(A), the probability of event A?

a

P(A) = 0.32

b

P(A) = 0.22

c

P(A) = 0.34

d

P(A) = 0.38

Let event C be the event that the game ends in a tie.

What is P(C), the probability of event C?

a

P(C) = 0.44

b

P(C) = 0.33

c

P(C) = 0.55

d

P(C) = 0.25

Define event B as the event that roommate B wins the game and thus does not have to wash the dishes. What is the probability
that roommate B wins the game?

a

P(B) = 0.67

b

P(B) = 0.43

c

P(B) = 0.33

d

P(B) = 0.50

What is the complement of event A?

A^c= event A

A^c = event A or event C                A^c = event B or event C

A^c = event C

The probability of N is

a

P(A) = 0.32

b

P(A) = 0.22

c

P(A) = 0.34

d

P(A) = 0.38

Explanation / Answer

Probability of A choosing Rock = PA(R) = 0.36

Probability of A choosing Paper = PA(P) = 0.32

Probability of A choosing Scissor = PA(S) = 0.32

Probability of B choosing Rock = PB(R) = 0.22

Probability of B choosing Paper = PB(P) = 0.25

Probability of B choosing Scissor = PB(S) = 0.53

What is P(A), the probability of event A?

Note: Choices of A are independent to that of B.

There are following possibilites of A winning,

PA = P1 + P2 + P3 = 0.1908+0.08+0.0704 = 0.3412

Answer: Option C

What is P(C), the probability of event C?

There are following possibilites of a Tie,

PC = P1 + P2 + P3 = 0.0792+0.1696+0.08 = 0.3288 = 0.33 (Approx.)

Answer: Option B

What is P(B), the probability of event B?

There are following possibilites of B winning,

PB = P1 + P2 + P3 = 0.0704+0.1696+0.09 = 0.33

Answer: Option C

What is the complement of event A?

The complement of A winning is either A losing (Event B) or a Tie (Event C).

Hence Ac = Event B or Event C