Question

Find the sum of the first 38 terms of the arithmetic sequence: 3, 8, 13, 18, 23, ...

Answer 1

Which series is it?

Answer 2

a=3
n=38
d=5
\[sum=n\frac{(2a+(n-1)d)}{2}\]

Answer 3

Its in the AP, because every next term has a constant difference with the preceding term

Answer 4

So @Jonask Formula holds for it , apply and get the result.