Explanation

To find the Arithmetic Mean (AM), we need to add up all the numbers and divide by the number of items in the list.

First, let's add up the numbers:

6 + 12 + 18 + 24 + 30 = 90

Next, count the number of items in the list:

There are 5 numbers in the list.

Now, divide the sum by the count:

90 ÷ 5 = 18

So, the Arithmetic Mean is: 18