Question

Find the 10th term from the end of the progression
82 + 79 + 76 + … + 4.

Answer 1

This is an Arithmetic Progression (AP).

First term a = 82

Common difference d = 79 − 82

= −3

Last term l = 4

Formula for the nth term from the end:

nth term from end = l − (n − 1)d

= 4 − (10 − 1)(− 3)

= 4 + 27

= 31