Question

if an octahedral die is rolled 9 times, what is the probability that only the last 2 rolls will be a multiple of 3?

Answer 1

If there are 2 multiples of three out of 8, then it's 2/8 x 2/8 = 1/16.

Answer 2

hmmm

Answer 3

But then you need to guarantee that the others are NOT multiples of three, so...

Answer 4

1/16 x (6/8)^7 = 2187/262144 = approximately 0.008342742919921875

Answer 5

Thanks for the help OakTree!