Question

What is the sum of the first 25 terms of arithmetic sequence 19, 28, 37

Answer 1

Answer:

= 19

d = 28-19 = 9

Sn = {n{2*a + (n-1) * d}} /2

Here, n = 25

∴ S25 = {25{ 2*19 + (25-1) *9}} /2

= 3175