Find the sum of 23 terms of the AP 17, 12, 7, 2, –3, ….
To Find: The sum of 25 terms of the given AP series.
Sum of n terms of an AP with first term a and common difference d is given by
Here, a = 17, n = 23 and d = - 5
= - 874
Sum of 23 terms of the AP IS - 874.