Answer:

Step-by-step explanation:
Here, we want to calculate the moving averages
To calculate this, we sum up the sales value for a period (years) divided by the number of years
For example, to calculate the moving average for 3 years (2015-2017) , we sum up the sales value for these 3 years and divide by 3
We proceed as follows:
A) If we add the values for 2015-2017 , we get the moving average for 2016 which is the middle year.

B) To get B, we can use the 3-year moving average for 2017-2019
Mathematically, we have that as follows:

C) C is the 3-year moving average for 2016-2018
Mathematically, we have that as:

D) D is the 3-year moving average for 2019-2021
We have that as:

E) E is the 5-year moving average of the years 2015-2019
Mathematically:

F) F is the 5-year moving average of the years 2017-2021
Mathematically:
