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A bag of M&Ms contains 7 blue, 4 brown, 4 orange, 2 yellow, 3 red, and 3
green. Reaching into the bag, a person grabs 5 M&Ms.
What is the probability of getting 3 blues?

Respuesta :

Answer:

0.1248 = 12.48% probability of getting 3 blues.

Step-by-step explanation:

The M&Ms are chosen without replacement, which means that the hypergeometric distribution is used to solve this question.

Hypergeometric distribution:

The probability of x successes is given by the following formula:

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

In which:

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.

Combinations formula:

[tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

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

In this question:

7 + 4 + 4 + 2 + 3 + 3 = 23 total M&Ms, which means that [tex]N = 23[/tex]

Sample of 5 means that [tex]n = 5[/tex]

7 blue means that [tex]k = 7[/tex]

What is the probability of getting 3 blues?

This is P(X = 3).

[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 = 3) = h(3,23,5,7) = \frac{C_{7,3}*C_{16,2}}{C_{23,5}} = 0.1248[/tex]

0.1248 = 12.48% probability of getting 3 blues.