Find the 12th term from the end of the following arithmetic progression:
3, 8, 13, … 253
A.P is known for Arithmetic Progression whose common difference = an – an-1 where n > 0
a = a1 = 3, a2 = 8, l = 253
Common difference, d = a2 – a1 = 8 – 3 = 5
We know, nth term from end, bn = l – (n – 1)d where l is last term or a1 and d is common difference and n is any natural number
∴ b12 = 253 – (12 – 1)5
⇒ b12 = 253 – 60 + 5
⇒ b12 = 258 – 60
⇒ b12 = 198
Hence, 12thterm from end for the given A.P is 198