Question

Two APs have the same common difference. The first term of one of these is -1 and that of the other is -8. What is the difference between their 4 ℎ terms?

Answer 1

Given two A.P's have same common difference.

Also given first term of one A.P is -1 and the other A.P is -8.

Let the common difference be d.

4th term of the A.P whose first term is -1 = - 1 + 3d

4th term of the A.P whose first term is -8 = -8+3d

Difference between the 4th terms of the A.P's ⇒

- 1 + 3d - (-8 + 3d) or -8 + 3d - (-1 + 3d)

- 1 + 3d + 8 - 3d or - 8 + 3d + 1 - 3d

7 or - 7 is the difference between 4th terms of the given A.P's.