There are 15 red, 9 blue and 6 green balls in the box, identical to the touch. Take out 6 balls at random.

There are 15 red, 9 blue and 6 green balls in the box, identical to the touch. Take out 6 balls at random. What is the probability that 1 green, 2 blue and 3 red balls are taken out?

1. A big event consists of two small independent ones, here is its formula:
P (C) = P (A) * P (B)

Big Event: 1 green, 2 blue and 3 red balls
Substitute in the formula and get:
P (C) = 1 ball green and 2 ball blue and 3 ball blue and 4 ball red and 5 ball red and 6 red
And- multiplication
We get:
P (S) = P (h) * P (s) * P (s) * P (k) * P (k) * P (k)

To find a small event:
P (A) = favorable outcomes (m) / number of total outcomes (n)

There are 30 outcomes in total, because 15 red balls, 9 blue balls and 6 green balls (15 + 9 + 6 = 30)
P (k) = 15/30 = 0.5
P (c) = 9/30 = 0.3
P (h) = 6/30 = 0.2

Now we substitute in our formula:
P (C) = 0.5 * 0.3 * 0.3 * 0.2 * 0.2 * 0.2 = 0.00036