Explanation
Phew! Tricky one for sure. This question tests multiple concepts and will help you revise them. We'll be using filters, as well as quick table calculations (percent of total) for this one.
1) Firstly, let's drag Country and to the Rows shelf, and year (discrete) to the Columns shelf.
Then, drag Publications to the Text Icon in the Marks Shelf. The following is our view:

Explanation
A Pareto chart is a type of chart that contains both bars and a line graph, where individual values are represented in descending order by bars, and the ascending cumulative total is represented by the line.
On the primary axis, bars are used to show the raw quantities for each dimension member, sorted in descending order.
On the secondary axis, a line graph is used to show the cumulative total in percent format.

Explanation
As the names suggest, if we subtract the order date from the shipping date, we simply get the number of days between these 2 dates.
We can these use this calculated field in our charts, and can use COUNT, SUM, AVG etc with them according to our need.

Explanation
According to the official Tableau documentation:
Depending on the version the extract was created in, Tableau extract files can have either the .hyper or .tde file extension. Extract files are a local copy of a subset or entire data set that you can use to share data with others, when you need to work offline, and improve performance. For more information, see Extract Your Data.

Explanation
Using the Sample superstore as a reference, click on the manage metadata icon as follows:

We can rename a particular column name to make it easier to remember and use in Tableau. Let's change Order ID to oID as shown:

Now, we'll see oID when using this data source in Tableau. This WILL NOT affect the original data source.
The remote field name let's us see what the name of the column is in the ORIGINAL Data source.