Respuesta :

Answer:

[tex]\dfrac{1}{3}[/tex]

Step-by-step explanation:

Let A and B represent the following events.

A = At least one of a pair of fair dice lands of 5

B = Sum of the dice is 7

It two dice are rolled then total number of outcomes is 36.

A = {(1,5),(2,5),(3,5),(4,5),(5,5),(6,5),(5,1),(5,2),(5,3),(5,4),(5,6)} = 11

B= {(1,6),(2,5),(3,4),(4,3),(5,2),(6,1)}=6

A∩B = {(2,5),(5,2)}=2

[tex]P(A)=\dfrac{11}{36},P(B)=\dfrac{6}{36},P(A\cup B)=\dfrac{2}{36}[/tex]

We need to find the probability that at least one of a pair of fair dice lands of 5, given that the sum of the dice is 7.

[tex]P(A|B)=\dfrac{P(A\cup B)}{P(B)}[/tex]

[tex]P(A|B)=\dfrac{\dfrac{2}{36}}{\dfrac{6}{36}}[/tex]

[tex]P(A|B)=\dfrac{2}{6}[/tex]

[tex]P(A|B)=\dfrac{1}{3}[/tex]

Therefore, the probability that at least one of a pair of fair dice lands of 5, given that the sum of the dice is 7 is 1/3.

The probability that at least one of a pair of fair dice lands of 5, given that the sum of the dice is 7 is 1/3.

What is Probability?

The probability helps us to know the chances of an event occurring.

[tex]\rm{Probability=\dfrac{Desired\ Outcomes}{Total\ Number\ of\ outcomes\ possible}[/tex]

We know that the sum of the dice is already 7, therefore, the possible options that the sum of fair dice is 7 are,

S = {(1,6), (2,5), (3,4), (4,3), (5,2), (6,1)}

Now, we need that one of the two dice must give 5 as the output, therefore, the possible options are,

N = {(2,5), (5,2)}

As we know the formula for finding the probability, therefore, substitute the values,

[tex]\rm Probability(\text{One of the dice gives 5}) = \dfrac{Desired\ Outcomes\ n(S)}{Total\ Number\ of\ outcomes\ possible\ n(N)}[/tex]

[tex]\rm Probability(\text{One of the dice gives 5}) = \dfrac{2}{6} = \dfrac{1}{3}[/tex]

Hence,  the probability that at least one of a pair of fair dice lands of 5, given that the sum of the dice is 7 is 1/3.

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