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 fourth terms is

Answer 1

Ap 1 = a = -1
Ap 2 = a = -8
Thus
-1 + ( n -1 )d = -8 + ( n-1 )d
7 + 3d = 3d
Hence the d is same