Question

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

Answer 1

Answer:

Step-by-step explanation:

Answer 2

given :-

7 ( a7 ) = 11 ( a11 )

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

7a + 42d = 11a + 110d

7a - 11a + 42d - 110d = 0

4a - 68d = 0

a - 17d = 0

a = 17d ... ( i )

To find 18th term

a18 = a + ( n - 1 )d

a18 = a + 17d

a18 = 17d + 17d

a18 = 34d