A bag contains 10 green marbles and 4 yellow marbles. If two marbles are chosen at random, one at a time and without replacement, what is the probability of getting two green marbles?

Respuesta :

P(green), is 10/14=5/7 because there are 10 green marbles out of the total 14.
P(2nd green), is 9/13 because there are only 9 green marbles and only 13 total marbles. Then you multiply them 5/7 x 9/13 = 35/117

Answer:  The required probability of getting two green marbles is 49.45%.

Step-by-step explanation:  Given that a bag contains 10 green marbles and 4 yellow marbles. Two marbles are chosen at random, one at a time and without replacement.

We are to find the probability of getting two green marbles.

Let S denote the sample space for the experiment of choosing a marble from the bag and A denote the event of getting a green marble.

The, n(S) = 10 + 4 = 14   and   n(A) = 10.

So, the probability of event A will be

[tex]P(A)=\dfrac{n(A)}{n(S)}=\dfrac{10}{14}=\dfrac{5}{7}.[/tex]

After getting one green marble and not replacing, let S' denote the sample space for the experiment of choosing a marble from the bag

and

let B denote the event of getting another green marble.

Then, n(S') = 14 - 1 = 13    and    n(B) = 10 - 1 = 9.

Then, the probability of getting two green marbles is given by

[tex]P\\\\=P(A)\times P(B)\\\\=\dfrac{5}{7}\times\dfrac{n(B)}{n(S')}\\\\\\=\dfrac{5}{7}\times\dfrac{9}{13}\\\\\\=\dfrac{45}{91}\times100\%\\\\=49.45\%.[/tex]

Thus, the required probability of getting two marbles is 49.45%.