Tell whether the sequence is arithmetic. if it is, what is the common difference?

15. 1, 1 1/6, 1 1/3, 1 1/2

To tell whether the the sequence is arithmetic, we try to see if there is a common difference between the terms in the sequence. We do as follows:

1 1/2 - 1 1/3 = 1/6
1 1/3 - 1 1/6 = 1/6

Therefore, the sequence is arithmetic and the common difference is 1/6. Hope this answers the questions. Have a nice day.