Question

What is the common difference between successive terms in the sequence? 9, 2.5, –4, –10.5, –17, ... –11.5 –6.5 6.5 11.5

Answer 1

Solution :

i ) Given A.P :

9 , 2.5, -4 , -10.5, -17 ,...

common difference (d) = a2 - a1

= 2.5 - 9

d = - 6.5

••••

Answer 2

Answer:

Difference d=-6.5

Step-by-step explanation:

Given AP series is 9, 2.5, -4, -10.5, -17

Let a is the first term and d be the difference between terms

Then,  

Second term is a+d=2nd term

 9+d=2.5

 d=2.5-9

 d= -6.5

Let us confirm it for 3rd term

nth term of AP= a+(n-1)d

here n =3

= 9+(3-1)x (-6.5)

=9+2x(-6.5)

=9-13

=-4

Hence proved, 3rd term is -4.

Difference d=-6.5

Therefore, 2nd option -6.5 is the right answer