Area Man Who Talks a Lot About Teaching Teaches His First Full Day in >10
Years
-
I have taught demo and observational classes regularly since I left
full-time teaching but yesterday was the first time I taught every class
for the day. L...
3 years 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