Suppose we have two urns, Urn 1 and Urn 2. Urn 1 contains 9 red marbles and 11 white marbles. Urn 2 contains 3 red marbles and 13 white marbles. The experiment consists of first choosing an urn with equally likely probability, and then drawing a marble from that urn. What is the probability of choosing Urn 1 and a white marble?

Respuesta :

Answer:

P(x1∩W) = 11/40 = 0.275

the probability of choosing Urn 1 and a white marble is 0.275.

Step-by-step explanation:

Let x1 and x2 represent each urn 1 and 2 respectively,

And R and W represent red and white marbles respectively.

the probability of choosing Urn 1 and a white marble is

P(x1∩W) = P(x1) × P(W in x1) ......1

Where;

P(x1∩W) = the probability of choosing Urn 1 and a white marble

P(x1) = probability of selecting urn 1

P(W in x1) = the probability of choosing white marble in urn1

Since the two urn are of equal probabilities, the probability of choosing urn 1 is half;

P(x1) = 1/2

For urn 1;

Red marbles = 9

White marbles = 11

Total = 20

P(W in urn1) = 11/20

From equation 1;

P(x1∩W) = 1/2 × 11/20 = 11/40

P(x1∩W) = 11/40 = 0.275

the probability of choosing Urn 1 and a white marble is 0.275.

Using conditional probability, it is found that there is a 0.275 = 27.5% probability of choosing Urn 1 and a white marble.

Conditional Probability

[tex]P(B|A) = \frac{P(A \cap B)}{P(A)}[/tex]

In which

  • P(B|A) is the probability of event B happening, given that A happened.
  • [tex]P(A \cap B)[/tex] is the probability of both A and B happening.
  • P(A) is the probability of A happening.

In this problem:

  • Event A: Urn 1.
  • Event B: White marble.

Equally as likely to choose both urns, hence [tex]P(A) = 0.5[/tex].

In urn 1, 11 of the 11 + 9 = 20 marbles are white, hence:

[tex]P(B|A) = \frac{11}{20} = 0.55[/tex]

Applying conditional probability:

[tex]P(B|A) = \frac{P(A \cap B)}{P(A)}[/tex]

[tex]0.55 = \frac{P(A \cap B)}{0.5}[/tex]

[tex]P(A \cap B) = 0.55(0.5)[/tex]

[tex]P(A \cap B) = 0.275[/tex]

0.275 = 27.5% probability of choosing Urn 1 and a white marble.

A similar problem is given at https://brainly.com/question/14398287