Answer: 1/8
Explanation:
Pick any term and subtract off the previous term to get the common difference.
So,
13/40 - 1/5 = 13/40 - 8/40 = (13-8)/40 = 5/40 = 1/8
Or
9/20 - 13/40 = 18/40 - 13/40 = (18-13)/40 = 5/40 = 1/8
The positive common difference value indicates this arithmetic sequence is increasing.
