Question

The 20th term from the end of the AP 3, 8, 13, ..., 253 is
(a) 163
(b) 158
(c) 153
(d) 148

Answer 1

(b) 158
Here, a = 3, d = (8 - 3) = 5, l = 253 and n = 20^th
Now, n^th term from the end = [l - (n - 1)d]
20^th term from the end = [253 - (20 - 1) ⨯ 5]
= [253 - (19 ⨯ 5)] = (253 - 95) = 158
Hence, the 20^th term from the end of the AP is 158.