Question

If 7 times the7th term of an A.P is equal to the 11 times it's 11th term, then find its 18th term.

Answer 1

66 is the ANSWER.....

Answer 2

Answer:

Let 1st term is X

Common difference = d

7th term = X+(7-1)d

11th term = X+(11-1)d

ATQ

7×(X+6d) =11× (X+10d)

7X+42d = 11X+110d

4X= -68d

17D= -X

18th term = X+(18-1)d

========= X + 17d

=========X-X

=========0

So 18th term is 0.