Question

4) Find the four arithmetic means between -21 and -36.

Answer 1

-21, ___, ___, ___, ___, -36

You have to add the common difference, d, five times to -21 to get -36.

-21 + 5d = -36
5d = -15
d = -3

So the first mean is -21 - 3 = -24
The second is -24 - 3 = -27
and so on