Answer
$(1/36)^3 = 1/46656$
Work Step by Step
If the probability of an event is $x$, if the probabilities are independent, the probability of doing it 3 times in a row is $x^3$
The probability of rolling two 1's is $1/6*1/6$ or $1/36$. $(1/36)^3 = 1/46656$
