Question

Determine if the sequence below is arithmetic or geometric and determine the

common difference / ratio in simplest form.
20, 10, 5, ...

Answer 1

geometric, with a common ratio of 1/2

Explanation:

The sequence is geometric because you get successive trems by multiplying the previous term by a certain constant, the 'common ratio'. (If you got each successive term by adding or subtracting the same constant number each time, that would be an arithmetic sequence.)

In this case, it looks like you get each successive term when you multiply the previous term by 1/2.

Thus, the common ratio is 1/2.