Question

If 7 times the 7 term of an
a.P. Is equal to 11 times its 11 terms, then 18 term is

Answer 1

Step-by-step explanation:

let 'a' be the 1st term and 'd' be the common difference

then 7th term of A.P=a+6d

and 11th term of A.P=a+10d

7(a+6d)=11(a+10d)

7a+42d=11a+110d

7a-11a=110d-42d

-4a=68d

a=-17d

18 th term = a+17d

=-17d+17d

=0