Find the number of terms in each of the following APs :

7, 13, 19, . . ., 205

Given first term (a) = 7

Common difference (d) = n₂-n₁ = 13 - 7 = 6

a_n = 205

⇒ a_n = a + (n-1)d

205 = 7 +(n-1) 6

198 = (n-1) 6

(n-1) = 33

n = 34

Therefore 205 is 34^th term of the series.