Probability Question on different topics

[r_walid]

if I have 4 orange balls and 6 white balls in a jar. what is the probability of the following?

1- Pick 1 orange ball

2- pick 2 orange balls.

please explain the process in detail on how to obtain such answers.

Thanks

[mp2437]

1 - there are 4 orange balls, and a total of 10 balls in a jar. Probability to get 1 orange ball is 4/10.

2 - In order to get 2 orange balls, you need to first get 1, and then get another. Probability to get 1 orange ball = 4/10. Now that you removed 1 ball out of the 10 that were there, you have 3 orange balls left in a jar that has a total of 9 balls (since you removed 1 orange ball).

The probability to get 2 orange balls is (4/10) * (3/9) = 12/90 = 2/15