Question

What is the value of r of the geometric series

Answer 1

The correct option is 1.

Explanation:

The given geometric series is

`\sum_(n=1)^(3)1.3(0.8)^(n-1)`

It means the nth term of the given geometric series is

`a_n=1.3(0.8)^(n-1)` .... (1)

The nth term of an geometric series is

`a_n=ar^(n-1)` .... (2)

where, a is first term and r is common ratio.

From (1) and (2), we get

`a=1.3, r=0.8`

The value of r is 0.8. Therefore the correct option is 1.

Answer 2

.8

Explanation:

The r value of the geometric series is what we multiply by each time.

We are multiplying by .8 each time so that would be r