Question

find the 25th term from last term of the ap 3,8,13....,253

Answer 1

the answer is 25th = 123

Answer 2

Solution :

We have, l = Last term = 253

and,

               d = Common difference = 8 - 3 = 5

∴ 20th term from the end = l - (20 - 1)d

                                           = l - 19d

                                           = 253 - 19 × 5

                                           = 253 - 95 = 158