Question

8 term of an ap is half. it's second term and eleventh term is 1/2 more than 1/3 of it's fourth term ​

Answer 1

a + 7d = a + d/2

=>2a + 14d = a + d

a = -13d

a + 10d = 1/3(a + 3d) + 1

a + 10d -1 = 1/3(a + 3d)

3(a + 10d -1) = a +3d

3a + 30d -3 = a + 3d

2a + 27d =3

2(-13d) + 27d =3(since a = -13d)

-26d + 27d = 3

=> d = 3

a= -13d

=> a = -39

a + 14d = -39 + 42

hence a15 =3