(i)

a=3, d=5 -3=2, a_n =201

a_n= a +(n -1)d

201 =3 +2n – 2

N =100

Now, we have to find 12^th term from the last that means,

100^th – 11=89^th term

Then,

a₈₉ =a + (89 – 1)d

=3 +88

=179

Hence, the 12^th term from the end of the A.P. is 179.

(ii)

a=3, d= 8 -3 =5

a_n= 253

a + (n -1)d =253

3 + (n -1)5 =253

n=51

Now, we have to find 12^th term from the last that means,

51th -11 = 40^th term

Then,

a₄₀ = a + (n -1)d

= 3 + 39(5)

=198

Hence, the 12^th term from the end of the A.P. is 198

(iii)

a=1, d= 4 -1 =3

a_n= 88

a + (n -1)d =88

1 + (n -1)3 =88

n =30

Now, we have to find 12^th term from the last that means,

30^th -11 = 19^th term

a₁₉ = a + 18d

= 1 + 18(3)

=55

Hence, the 12^th term from the end of the A.P. is 198.