Question

A box contains 3 red balls and 4 green balls. If two balls are randomly selected in sequence, what is the possibility that a red ball and a green ball are picked out of the box?

Answer 1

There are 3 ways to pick the red ball and 4 ways to pick the green ball for a total number of events of `3xx4=12` ways to pick a red and green ball out of the box.

Explanation:

There is a total of 7 balls. The sample space for the number of ways of choosing two balls is `(7!)/(2!5!)=21` ways

P(red ball and a green ball) `=12/21=4/7~~0.57`

hope that helped