Given A.P. is 3, 8, 13, …, 253

Common difference, d= 5.

Therefore, we can write the given AP in reverse order as;

253, 248, 243, …, 13, 8, 5

Now for the new AP,

first term, a = 253

and common difference, d = 248 − 253 = −5

n = 20

Therefore, using nth term formula, we get,

a₂₀ = a+(20−1)d

a₂₀ = 253+(19)(−5)

a₂₀ = 253−95

a = 158

Therefore, 20^th term from the last term of the AP 3, 8, 13, …, 253 is 158.