Question

Q.4

Answer 1

For an A.P., 

`t_15=a+14d`

And, `t_8=a+7d`

Given that, 

`t_15-t_8=7`

`⇒ (a+14d)-(a+7d)=7`

`⇒7d=7`

`⇒d=1`

Thus, the common difference is `1.`