Question

What is the sum of the arithmetic sequence 174, 168, 162 …, if there are 33 terms?

2,541

2,574

2,607

2,640

Answer 1

The formula for the sum of n terms is
\[S=\frac{n}{2}[2a+(n-1)d]\]
where n is the number of terms, a is the first term and d is the common difference.
In the question n = 33, a = 174. Do you know how to find the common difference?