Question

Is the following sequence arithmetic? If so, identify the common difference. 2.9, 2.7, 2.5, 2.3,

Answer 1

The common difference is -2

Answer 2

Notice that 2.7 = 2.9 - 0.2; 2.5 = 2.7 - 0.2, and so on.  So the common difference is -0.2.