a. A sum of 7 is rolled exactly 2 times.

b. A sum of 7 is rolled at least 2 times.

c. A sum of 7 is rolled at most 2 times.

d. A sum of 7 or 11 is rolled exactly 5 times.

e. A sum of 7 or 11 is never rolled.

f. A sum of 7 or 11 is rolled the 3rd and 5th time only.