If 7 times the 7th term of an AP is equal to 11 times its 11th term, What is the value of 18th term

M4maths Previous Puzzles

05 Jun 2019 AP

If 7 times the 7th term of an AP is equal to 11 times its 11th term, What is the value of 18th term ?

OPtion

1) 36
2) 56
3) 32
4) 64
5) 85
6) 80
7) 88
8) 0
9) 27
10) None of these

Solution

7a+42d=11a+110d
68d=-4a
a=-17d
now 18th term...a+17d as nth term is a+(n-1)d
a+17d=-17d+17d=0
hence answer is 0

Correct Option: 8 Best Solution (3)