Getting two consecutive $6$'s A standard six-sided die is rolled until two consecutive 6s appear. Find the expected number of rolls. Please see that this is a language problem. What do they mean by expected number of rolls? Should the answer be 36? Or 42?

The expected value of the number of rolls is defined as
$$
\sum_{k=1}^\infty k\cdot p_k
$$
where $p_k$ is the probability that it will take exactly $k$ rolls to make 2 consecutive 6's appear. This is what they mean, but using the definition directly may not be the best way to do this problem. 
