Richard can make 8 dough balls in two hours. If the amount of time is directly proportional to the number of dough balls, how many hours have passed if he made 18 dough balls?

Given a = {(1, , 5)(6,4)}, b = {(2,0)(4, ,5)(0, 0)) and c = {(1, 1)(0, 2)(0, 3)(0, ,5)}, answer the following multiple choice question: from the list of sets a, b, and c, state the domain of set b. domain of set b: {0, 6,5} domain of set b: {2, 4,-4, 0} set b does not have a domain