If no two numbers are the same, then there's no mode.
We have the following arithmetic series:
4, 13, 22, 31, 40
The common difference is given by:
13-4 = 9
22-13 = 9
31-22 = 9
40-31 = 9
Since it is an arithmetic series, the difference is constant.
Answer:
The common difference is:
9
option 4
