Question

Find the four arithmetic means between 10 and -30. What is the common difference?

Answer 1

Ummm... I'm not sure if it 100% right but ....

a = -30
a_6 = 10
10 = -30+5d
d = 8
-30 -22 -14 -6 2 10
So , the answer -22 -14 -6 2

Answer 2

The common difference is d=8. The four arithmetic means are:
-22,-14,-6,2