Question

Which of the following is an arithmetic sequence?–20, –25, –30, –35, –45, ...

–15.6, –12.9, –10.2, –7.5, –4.8, ...

3.1, 6.2, 12.4, 24.8, 49.6, ...

7.2, 3.6, 1.8, 0.9, 0.45, ...

Answer 1

B) -15.6,-12.9,-10.2,-7.5,-4.8

This is an arithmetic sequence. 

Answer 2

Answer:

The correct option is 2.

Step-by-step explanation:

A sequence is called arithmetic if it has common difference.

In sequence 1,

–20, –25, –30, –35, –45, ...

$d_1=-25-(-20)=-5$

$d_2=-45-(-35)=-10$

$d_1\neq d_2$

Therefore it is not an arithmetic sequence.

In sequence 2, the common difference is

$d=-12.9-(-15.6)=2.7$

Therefore it is an arithmetic sequence and option 2 is correct.

In sequence 3,

$d_1=6.2-3.1=3.1$

$d_2=12.4-6.2=6.2$

$d_1\neq d_2$

Therefore it is not an arithmetic sequence.

In sequence 4,

$d_1=3.6-7.2=-3.6$

$d_2=1.8-3.6=-1.8$

$d_1\neq d_2$

Therefore it is not an arithmetic sequence.

Therefore only option 2 represent arithmetic sequence.