There are 7 red balls and 9 white balls in the urn, what is the probability that two balls will turn out to be multi-colored.

The probability of taking out 1 red and 1 white ball is:
P = C 17⋅C 19 / C 216 = 7⋅9 / 120 = 0.5250
Here the combinations are calculated as follows:
C 17 = 7! / (1! ⋅ (7−1)!) = 7! / (1! ⋅6!) = 7/1 = 7
C 19 = 9! / (1! ⋅ (9−1)!) = 9! / (1! ⋅8!) = 9/1 = 9
C 216 = 16! / (2! ⋅ (16−2)!) = 16! / (2! ⋅14!) = (15⋅16) / (1⋅2) = 120