Question

3.If the 8th term of an A.P.is 31 and the 15th term is 16 more thanthe11th term,findtheA.P.

Answer 1

Answer:

Step-by-step explanation:

3,7,11,15, so on.......

Answer 2

Step-by-step explanation:

Let a be the first term and d be the common difference of the A.P.

We have

a8 = 31 a15 = 16 + a11

⇒ a + 7d = 31 and  a + 14d = 16 + a + 10d

⇒ a + 7d = 31 and  4d = 16

⇒ a + 7d = 31 and d = 4

⇒ a + 7 × 4 = 31 

⇒ a + 28 = 31 

⇒ a = 3 Hence the A.P. is a, a + d, a + 2d, a + 3d, . . . . . . . i.e.   3, 7, 11, 15, 19, .