Given: An A.P: 3, 8, 13, …… , 253

Here a = a₁ =

d = a₂ – a₁ = – =

a_n = , where 253 is the last term

a_n = a + (n – l)d

∴ = + (n – 1)

⇒ = + n –

⇒ n = +

∴ The 20^th term from the other end would be

1 + ( – ) = + 1 =

∴ a₃₂ = + ( – 1) ×

= + ×

= + =