Question

Find the 20th term of the A.P 9, 13, 17,21...​

Answer 1

Answer:

Given AP is 9,13,17,21,....

Here, first term =a=9

Common difference=d=13−9=4

n

th

term is given by,

a

n

=a+(n−1)d

For 20

th

term put n=20.

a

20

=9+(20−1)4

=85.