Question

What is the sum of the arithmetic sequence 3, 9, 15…, if there are 34 terms?

2,467

2,684

3,072

3,468

Answer 1

The sum of an arithmetic sequence is given by;

S = n/2 [2(first) + (n-1)d],

where d is the difference, 'first' is the first term, and n is the number of terms you are summing.

Hence;

S = 34/2 [2(3) + (33)6] = 3468