Question

Find the 15", 24" and n" term (general term) of an A.P. given by 3, 15,
27, 39,..​

Answer 1

15th term =

24th term =

nth term (general term) = a + (n-1)d

We already know that nth term is a + (n-1)d where a is the first term in the A.P and d being the common difference between the terms.

According to the question,

a = 3

d = 12

So applying the general term formula we get

When n = 15,

= a + (n-1)d

= 3 + (15-1)12

= 3 + (14)12

= 3 + 168

= 171

When n = 24

= a + (n-1)d

= 3 + (24-1)12

= 3 + (23)12

= 3 + 276

= 279

So the 15th term of this A.P is 171 and the 24th term of this A.P is 279.

Answer 2

It is the answer for the sum