Question

Two APs have the same common difference. The first term of one of these is -1 and that of the other is -8. Then the difference between their 4th term is
-1
-8
8
7

Answer 1

Step-by-step explanation:

let the common difference be d.

now,

4th term of ap with first term -1 is=

a(4)=-1+(4-1)d

a(4)=-1+3d

now,

4th term of ap with first term -8 is=

a(4)=-8+(4-1)d

a(4)=-8+3d

now,

their difference= -1+3d-(-8+3d)

=-1+3d+8-3d

=-1+8

=7