5 x 3^n

Question

a)15,30,45,60
b)5,15,45,135
c)0,15,45,135
d)15,45,135,405

Answer 1

3^n: 1,3,9,27
so, which is 5 times that?
Hint: only one sequence starts with 5

Answer 2

just took the test, the answer is
d) 15,45,135,405