Question

A box contains 10 green marbles and 11 white marbles. If the first marble chosen was a green marble, what is the probability of choosing, without replacement, a white marble? Express your answer as a fraction or a decimal number rounded to four decimal places.

Answer 1

11/20

Explanation:

At the beginning, the number of marbles in the box are:

10 green marbles

11 white marbles

The first marble chosen is green, and then it is not replaced in the box. Therefore, the number of green marbles left in the box is 9.

Therefore, the total number of marbles left in the box is:

`n=9+11=20`

Now we want to find the probability to choose a white marble. The number of white marble is

`w=11`

Therefore, the probability of choosing a white marble is:

`p(w)=(w)/(n)=(11)/(20)`