Determine if the sequence below is arithmetic or geometric and determine the common difference/ratio simplest form

Question

45,15,5

Answer 1

geometric

common ratio = 1/3

45, 15, 5, 5/3, 5/9, ....

nth term = an = a1(r)^(n-1)

an=45(1/3)^(n-1)

n=3, a3 = 45(1/3)^2 = 45(1/9) =5

n=2, a2 = 45(1/3)^1 = 45(1/3) = 15

n=1, a1 = 45(1/3)^0 = 45(1) = 45