Question

if the 2nd term of ap is 13 and the 5th term is 25 what is its 7th term ?

Answer 1

let a be the first term of ap  and d be common difference
According to question
an= a+(n-1)d
A2= a+d=13  ............................................................................. mark as 1
A5= a+ (5-1)d=a+4d=25  ...........................................................  mark as 2
on subtract 2 from 1,we get
3d=12
d=4
on putting value of d in 1 , we get
a=9
A7=a+(7-1)d=a+6d
9+6x4
9+24
33