17 times the 7" term of an AP is equal to 11 times its 11" term, then

1.	17 times the 7" term of an AP is equal to 11 times its 11" term, then find its 18" term.
Answer» We know nth term of an APan = a + (n-1)d Then,a7 = a + 6da11= a + 10d As per given condition7(a + 6d) = 11(a + 10d)11a - 7a = 110d - 42d4a = 68da = 68/4 da = 17d........ (1) Then 18th term= a + 17d Put value of a from eq(1) We get= 17d + 17d= 34d

17 times the 7" term of an AP is equal to 11 times its 11" term, then find its 18" term.

Answer»

We know nth term of an APan = a + (n-1)d

Then,a7 = a + 6da11= a + 10d

As per given condition7(a + 6d) = 11(a + 10d)11a - 7a = 110d - 42d4a = 68da = 68/4 da = 17d........ (1)

Then 18th term= a + 17d

Put value of a from eq(1) We get= 17d + 17d= 34d