We are asked to determine the probability of rolling a 1 or a 6. To do that we will use the following relationship:
Therefore, we need to add the probability of getting a 1 and the probability of getting a 6.
The probability is the quotient of the number of occurrences divided by the sum of the total number of occurrences, like this:
Solving the operations:
Now, we determine the probability of getting a 6:
Now, we add the probabilities:
The probability is 11/20.