Question

The 17th term of Ap is 5 more than its 8th term. if 11th term
of Ap is 43.Find its nth term ​

Answer 1

Step-by-step explanation:

A/Q

a₁₇ = 5 + 2a₈ and a₁₁ = 43

we know nth of an A.P. = a + (n-1) d where a = first term

d = common difference of A.P

therefore

a + (17 - 1) d = 5 + 2{ a + (8 - 1 ) d}

a + 16 d = 5 + 2a + 14d 2d - a = 5 .......(1)

also a + (11 - 1)d = 43 a + 10d = 43 .........(2)

solving 1 and 2 gives 12d = 48 d = 4

a = 3

hence nth tern would be = 3 + (n-1)4 ans