You have a bag of enough ping pong balls such that each one has exactly one of the numbers from 57 to 133 painted on it. What is the probability that if you randomly select five of the balls from the bag all of the numbers on the selected balls will be divisible by 3 or by 7?

Respuesta :

Answer:

The answer is "0.338"

Step-by-step explanation:

We have 133-57+1 = 77 balls to pocket, essentially.  See the number of words around 57 and 133 and separable by 3 (132):

[tex]a_o = 57\\d = 3\\A_n = 132\\\to 132 = 57 + (n-1) \times 3\\\\\to 132= 57+3n-3\\\\\to 135-57 =3n\\\\\to 3n=78\\\\\to n=\frac{78}{3}\\\\\to n= 26[/tex]

Therefore, the number for a number around 57 and 133 divisible by 3 = 26  

The probability required[tex]=\frac{26}{77} = 0.337[/tex]

Using the hypergeometric distribution, it is found that there is a 0.0128 = 1.28% probability that if you randomly select five of the balls from the bag all of the numbers on the selected balls will be divisible by 3 or by 7.

The balls are chosen without replacement, hence, the hypergeometric distribution is used to solve this question.

Hypergeometric distribution:

[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}C_{N-k,n-x}}{C_{N,n}}[/tex]

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

The parameters are:

x is the number of successes.

N is the size of the population.

n is the size of the sample.

k is the total number of desired outcomes.

Multiples in the interval:

  • From 57 to 132, there are (132 - 57)/3 + 1 = 26 multiples of 3.
  • From 63 to 133, there are (133 - 63)/7 + 1 = 11 multiples of 7.
  • 63, 84, 105, 126 are multiples of both.

Hence, [tex]k = 26 + 11 - 4 = 33[/tex]

As for the other parameters:

  • 133 - 57 = 76 balls, hence [tex]N = 76[/tex]
  • 5 are chosen, hence [tex]n = 5[/tex]

The probability is P(X = 5), hence:

[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}C_{N-k,n-x}}{C_{N,n}}[/tex]

[tex]P(X = 5) = h(5,76,5,33) = \frac{C_{33,5}C_{43,0}}{C_{76,5}} = 0.0128[/tex]

0.0128 = 1.28% probability that if you randomly select five of the balls from the bag all of the numbers on the selected balls will be divisible by 3 or by 7.

A similar problem is given at https://brainly.com/question/24826394