First term, a = 4

Common difference, a₂ – a₁ = 14 – (4) = 10

Let the no of terms be n

We know, that nth term of an AP is 

a_n =a + (n – 1)d

where a is first term and d is common difference.

254 = 4 + (n – 1)10

⇒ 250 = (n – 1)10

⇒ n – 1 = 25

⇒ n = 26

10^th term from last will be 17^th term from starting

And a₁₀ = a + 16d

= 4 + 16(10)

= 164