Question

find the nth term of this sequence
15,12,9,6

Answer 1

Question :

To find the nth term of the given series

15,12,9,6

Theory :

In AP series :

${\purple{\boxed{\large{\bold{a _{n} = a + (n - 1)d}}}}}$

Solution :

Given series : 15,12,9,6

It can be observed that differnce between terms in the given series is same .

⇒Given series in AP

common difference ,d = 12-15 =-3

first term = 15

Nth term

$a _{n} = a + (n - 1)d$

$\implies \: a_{n} = 15 - 3n + 3$

$\implies \: a_{n} = 15 + (n - 1) - 3$

$\implies \: a_{n} = 18 - 3n$

It is the required solution!