Which answer describes this type of series - 20-18-15-11 - ...

A). Arithmetic

B). Geometric

C). Neither

D). Both

Arithmetic sequences have a common difference, while Geometric sequences have a common ratio.

In the sequence - 20, - 18, - 15, - 11 ..., there is not a common difference. This is because there is a + 2 increase between - 20 and - 18 but a + 3 difference between - 18 and - 15, then + 4 increase between - 15 and - 11.

This means it is not Arithmetic, which means it can't be both either.

This leaves us with B and C, so we have to see if there is a common ratio.

To find common ratio, divide any 2 terms in the sequence.

Let's choose - 18 and - 15.

-18 / - 15 = 1.2

Now let's see if this works for each term.

To do this, multiply each term by 1.2 to see if it results in the next term.

-20 • 1.2 = - 24 This doesn't work, so there is no common ratio.

This means the sequence is neither Arithmetic nor Geometric.

So the answer is C. Neither.

The answer is C) Neither because their is no consistency in adding, subtracting, multiplying, or dividing