# What is the 25th term of the arithmetic series 9, 15, 21, … ?

##### 1 Answer
Nov 7, 2015

$147$

#### Explanation:

Let $\left({x}_{n}\right) = \left(9 , 15 , 21 , 27 , \ldots \ldots .\right)$ be the arithmetic sequence.

The common difference is $d = {x}_{n + 1} - {x}_{n} = 6$.
The first term is $a = 9$.

The general term is given by ${x}_{n} = a + \left(n - 1\right) d$.

$\therefore {x}_{25} = 9 + \left(24 - 1\right) \cdot 6$

$= 147$