For what value of n, are the nth terms of two APs: 63, 65, 67, . . . and 3, 10, 17, . . . equal?
Find the 20th term from the last term of the AP : 3, 8, 13, . . ., 253.
We have
3, 8, 13,.....253
Here, a = 3
d = 5 l = 253
and n = 20
We know that,
nth term from the end is given by l – (n – 1)d i.e., 20th term from the end
= 253 – (20 – 1)5
= 253 – (19 x 5)
= 253 – 95 = 158