Question

Find the common ratio of the geometric sequence: -320,80,-20,5

Answer 1

Answer: -0.25

Explanation:

320/80=4

5/-0.25= -20

-20/ -0.25=80

80/-0.25=-320

That’s how I double confirm the answer I got works.

Answer 2

-1/4 if you prefer the answer written as a fraction.

-0.25 is you prefer the answer written as a decimal.

Explanation:

Common ratio of a geometric sequence can be found by doing term divided by previous term.

That is you could do:

80/-320

or

-20/80

or

5/-20

If all these ratios are not equal, it isn't a geometric sequence and does not have a common ratio.

Let's see what these reduce to:

80/-320=1/-4 =-1/4 or -0.25

-20/80=-1/4 or -0.25

5/-20=1/-4=-1/4 or -0.25

So the common ratio is -0.25 or yo you can write it as -1/4.