[Mailbag] What Do You Do with the Ideas You Used to Call “Mistakes”

Guillaume ParĂ©, in the very interesting comments of my last post where I
urged us to reconsider mistakes: I do agree with what is written, but I am
still w...
1 week ago
The answer is 150.
ReplyDeleteIf three dice are thrown, the probability of NOT getting triple sixes is 1(1/6)^3 = 215/216. So the probability of not getting triple sixes in n throws is (215/216)^n
Now we solve an inequality.
(215/216)^n < 0.5
log[(215/216)^n] < log(0.5)
n * log(215/216) < log(0.5)
n > log(0.5)/log(215/216) = 149.37...
n >= 150