Question

Which answer describes the type of sequence?

Answer 1

Answer:

it is geometric

Step-by-step explanation

We have been given with the series

200,40,8,1.6

Arithmetic sequence is the sequence in which difference between consecutive terms is same that is common difference d

d=a_2-a_1

d=40-200=-160   herea_2=40,a_1=200

d=8-40=-32          herea_2=8,a_1=40

We can see the difference is not same

Hence, the given sequence is not arithmetic sequence.

Geometric sequence is the sequence in which ratio of consecutive terms is same that is common ratio r

r=\frac{a_2}{a_1}

r=\frac{40}{200}=\frac{1}{5}   herea_2=40,a_1=200

r=\frac{8}{40}=\frac{1}{5}          herea_2=8,a_1=40

r=\frac{1.6}{8}=\frac{1}{5}             herea_2=1.6,a_1=8

We can see the ratio is  same.

Hence, given sequence is geometric

Therefore, Option 1 is correct given sequence is geometric.

Answer 2

200 : 5 = 40
40 : 5 = 8
8 : 5 = 1.6
1.6 : 5 = 0.32