A sequence of numbers begins with 12 and progresses geometrically. Each number is the previous number divided by 2.

Which value can be used as the common ratio in an explicit formula that represents the sequence?

2

6

12

The common ratio is the current number divided by the previous. So the ratio is 1/2

The sequence is 12, 6, 3, 3/2, 3/4 ...

You can obtain any number multiplying the previous number times 1/2.

6 = 12 * (1/2)

3 = 6 * (1/2)

3/2 = 3 * (1/2)