Problem Statement
Find the $20^{\text{th}}$ term from the last term of the AP: $3, 8, 13, \dots, 253$.
Verified Solution & Marking Scheme
Identify AP Parameters
First term $a = 3$, common difference $d = 8 - 3 = 5$, last term $l = 253$.
Apply Formula for nth Term from End
$a_n(\text{from end}) = l - (n - 1)d$
For $n = 20$:
$a_{20}(\text{from end}) = 253 - (20 - 1)(5) = 253 - 19(5) = 253 - 95 = 158$