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

Given: a = - 1

A = - 8

To find: a4 -A4

Formula Used: nth term of an AP is:

an = a + (n - 1) d

Explanation:

Let a and A be the first terms of Two AP’s.

a = - 1

A = - 8

Let d and D be the common differences of two AP’s.

D = d ……. (i)

Let a4 and A4 be the 4th terms of two AP’s.

As we know, nth term of an AP is

an = a + (n - 1) d

where a = first term

an is nth term

d is the common difference

a4 -A4 = a + 3d – (A + 3D)

= a + 3d - A - 3d (using ( i ) )

= a - A

= - 1 - (- 8)

= -1 + 8

= 7

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos  Champ Quiz | Arithmetic Progression34 mins  Champ Quiz | Arithmetic Progression30 mins  Quiz | Arithmetic Progression44 mins  NCERT | Fundamental Theorem Of Arithmetic45 mins  Lets Check Your Knowledge in A.P.49 mins  Arithmetic progression: Previous Year NTSE Questions34 mins  NCERT | Questions on General Term of an A.P47 mins  Quiz on Arithmetic Progression Quiz32 mins  NCERT | Arithmetic Progression36 mins  Fundamental Theorem of Arithmetic- 143 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation view all courses 