Given A.P is 4, 9, 14,…

Here, a₁ = a = 4, a₂ = 9

Common difference, d = a₂ – a₁ = 9 – 4 = 5

We know, a_n = a + (n – 1)d where a is first term or a₁ and d is common difference

∴ a_n = 4 + (n – 1)5

⇒ a_n = 4 + 5n – 5

⇒ a_n = 5n – 1

Now, to find which term of A.P is 254

Put a_n = 254

∴ 5n – 1 = 254

⇒ 5n = 254 + 1

⇒ 5n = 255

⇒ n = 51

Hence, 51^st term of given A.P is 254