Which sequence is geometric and has 1/4 as its fifth term and 1/2 as the common ratio?

Question

A. 1, 1/2, 1/4, 1/8 B. 1/4, 1/2, 1, 2 C.1/72, 1/36, 1/18, 1/9 D. 8, 4, 2, 1

Answer 1

a₅ = a₁(r)^n-1

 

1/4 = a₁(1/2)⁴

1/4 = a₁((1/16)

4 = a₁

 

Now your selections do not contain the solution: 4, 2, 1, 1/2, 1/4.