Question

Two A.Ps have the same common difference. If the first terms of each A.Ps are-1 and -8 then find the difference between the fourth terms

Answer 1

The difference between the fourth terms is 7

Explanation:

Solution:

For 1st A.P

Given

First term a = -1

common difference = d

n = number of term

Now by formula of A.P we get

`T_n = a +(n-1)d`

For n =4

`T1_4= -1+(4-1)d=-1+3d`

For 2nd A.P

First term a = -8

common difference = d

n = number of term

Now by formula of A.P we get

`T_n = a +(n-1)d`

For n =4

`T2_4= -8+(4-1)d=-8+3d`

Difference Between the Fourth terms=
`T1_4- T2_4=-1+3d-(-8+3d)= -1+3d+8-3d=7`