## Precalculus (10th Edition)

$\frac{1}{18}.$
According to the Multiplication Principle, if we have $p$ selections for the first choice, $q$ selections for the second choice, then we have $p\cdot q$ different ways of selections. Hence here we have a total of $6\cdot6=36$ outcomes. Out of these $36$ possible outcomes, the following have a sum of $11$: $[6,5],[5,6]$. We know that $\text{probability}=\frac{\text{number of favourable outcomes}}{\text{number of all outcomes}}=\frac{n(E)}{n(S)}.$ Hence, the probability of having a sum of $11$ is: $\text{probability}=\frac{2}{36}=\frac{1}{18}.$