Question

Which of these is not a geometric sequence?

A: 3, 6, 12, 24, ...

B: 250, 50, 10, 2, ....

C: 5, 15, 45, 135, ...

D: 4, 12, 20, 28, ...

Answer 1

Choice D isn't a geometric sequence. There isn't a common ratio between 4,12,20,28.

Answer 2

D: 4, 12, 20, 28, ...

Explanation:

The least common multiple (m. C. M.) Of two or more numbers is the smallest common multiple other than zero. To find the least common multiple of two or more numbers we must decompose the number into prime factors.

In the case of option D, the multiplication of the previous number by a common multiple does not follow in an ascending or descending line and therefore does not have a geometric sequence.