Question

The 19th term of an AP is equal to 3 times it's sixth term. If its 9th term is 19. Then find the AP

Answer 1

a19 = 3 a6
Therefore

a+18d = 3( a+ 5d )

a + 18d = 3a + 15d

3d = 2a ----------------------------------- 1


Given --:. A9 = 19

Therefore

a + 8d = 19 ---------------------------------- 2

Multiply 2 to equation 2

Therefore

2a + 16d = 38

From 1 ( 2a = 3d )

Therefore

3d + 16d = 38

19d = 38

d = 2

From 1

2a = 3d

2a = 3 × 2

a = 3

Therefore the AP is 3 , 5 , 7 , 9 , 11 , 13 , 15, ......




HOPE IT HELPS!!!!!