Find out how many gold medals each athlete won in the 2008 Olympics
Graphical user interface, text, application, website Description automatically generated

Drop Athlete to Rows and 2008 golds to the Text. Drop gold medals to the view. Your view will look like this:
Graphical user interface, text, application Description automatically generated

Now we need work on "won at least 4 golds in 2012 Olympics"
Drop years to filters and select 2012.
Drop Gold Medals to filter and mention 4 in range of values (as we need to find athletes who won at least 4 gold medals) Graphical user interface Description automatically generated

Final view:
Graphical user interface, text, application, chat or text message Description automatically generated

All are false here.
Refer: https://help.tableau.com/current/pro/desktop/en-us/maps_shapefiles.htm

Explanation
Use join Calculations while joining two tables.

Explanation
Approach 1 - Using Groups
Drop the Customer ID to the Rows.
Add sub-category to the filter and select phone.
Add Order date to the filter and select the year 2014.

Select all the customers and click on paper clip icon to create the group.
So here we got all the customers who have purchased any product in the Phones subcategory in 2014.
Edit the group and select Include other

Clear the filter shelf, and again add Order date to the filter and select 2015.
Drop Sales to the Text.
Add 'Percent of Total' Quick Table Calculation to the Sales field.
Your view will look like this:

Approach 2 - Using LOD
Create a LOD expressions as:

It will return 1 for the customers who have purchased any product in the Phones sub-category in 2014. For others, it will return 0.
Drop this field to the Rows and add Order date to the filter and select the year 2015.

Refer: https://help.tableau.com/current/pro/desktop/en-us/maps_howto_choropleth.htm