Question

find the 15th term of an ap3,6,9....using suitable formula​

Answer 1

Here given first term a = 3 and common difference d = 3....and it is given that n = 15.
now, a15 = a + 14d
= 3 + 14×3
= 3 + 42 = 45.

Answer 2

Answer:

45

Step-by-step explanation:

A.P. - 3,6,9....

Common difference d = 6-3=9-6=3

$a_1=3$

Formula of nth term = $a_n=a+(n-1)d$

Substitute n = 15  

$a_{15}=3+(15-1)3$

$a_{15}=3+(14)3$

$a_{15}=45$

Hence the 15th term of an given A.P. is 45