Question

A bag has 9 red marbles and 6 green marbles. How do you find the probability of drawing a green marble, replacing it, and drawing another green marble?

Answer 1

`4/25`

Explanation:

First, we have the probability of drawing a green marble as 6 out of (6+9), which is `6/15`.

After that, we replace the green marble into the bag. At this moment, the bag becomes the same as it is before a green marble is drawn, i.e. there are still 6 green marbles and 9 red ones.
If we are too draw another green marble, the same probability, `6/15`, will be resulted.

As both requirements have to be fulfilled, the required probability is the multiplication of both,
`=6/15*6/15`

`=36/225`

`=4/25`