Hello Econ Savages, I wanted to give you some extra side notes to help you with Absolute and Comparative Advantages. I am also going to attach a video to show you how to calculate opportunity cost and determine who has a comparative advantage.

Whenever you are given Absolute and Comparative problems, you must understand some of the terms they will give you. I am going to give you a short and sweet definition.
An output problem= total amount of product produced with the resources giving.
An input problem = the total amount of hours, days, people, acres to produce that product.
Absolute advantage= a country that can make more of a product (output problems) ,or make a product in less time or fewer resources (input problems)
Comparative advantage= a country having a smaller opportunity cost. ( they are giving up less to make a product).
You must understand the reason why we trade, is so that we do not waste our resources. 
So everybody wants to trade something. It is in their best interest. 
There are 4 things we look for when doing absolute and comparative problems:
•	Is this an input or output problem
•	Who has the absolute advantage?
•	What is each countries opportunity cost for making each product?
•	Who has comparative advantage?

So if I give you the scenario below, saying the amount of cars and shirts they can produce when using all their resources:

Countries | Cars | Shirts
Sweden | 15 | 3
Canada | 10 | 30

First based on the scenario, this is an output problem
Second, I can look at the chart to determine absolute advantage ( Sweden can make more cars, so they have the absolute advantage in cars, while Canada can produce more shirts, so they have the absolute advantage in shirts) 
Absolute is easy to find, but we do not base trade on absolute, we base it on comparative advantage.
To find comparative advantage, we must find the opportunity cost of each countries production of each product.
To solve for opportunity cost in an output problem, I take the amount that the country can make in the opposite box and make that the numerator, while the number in the box you make that the denominator. ( opposite over inner). Break your fractions down to decimals at the end.
Countries | Cars | Shirts
Sweden | 15     ( 1car=3/15 or .20) | 3      ( 1shirt= 15/3 or 5)
Canada | 10      (1 car=30/10 or 3) | 30    ( 1 shirt= 10/30 or .33)

So now we can see that for every car Sweden makes, they give up .20 of a shirt.
For every car that Canada makes, they give up 3 shirts
Canada gives up too much to make one car, so it is best that they trade, and because Sweden’s opportunity cost is smaller in cars, Sweden has the comparative advantage and should trade cars, while Canada should trade away shirts because their opportunity cost is smaller than Sweden’s in the shirt column. 

Now let’s look at an input problem:
 To solve for opportunity cost in an input problem, I take the amount in the  box and make that the numerator, while the number outside  the box you make that the denominator. ( inner over opposite). Break your fractions down to decimals at the end.
For an input problem the scenario would say the amount of days it takes to make one car or one shirt.

Countries | Cars | Shirts
Sweden | 15     ( 15/3 = 5) | 3    (  3/15=.20)
Canada | 10      (10/30=.3)) | 30   (  30/10=3)

First we acknowledge that this is an input problem based off the scenario
Second, Absolute changes, bc now Canada has the absolute bc it takes them less days to make one car, and Sweden has the absolute advantage in shirts, bc it takes them less days to make a shirt.
Third we find the opportunity cost of each.
Fourth, the smaller opportunity cost is the comparative advantage. So Canada trades cars and Sweden trade shirts. 

You can click on the link below to see another problem of solving comparative advantage for output and input problems.

https://www.youtube.com/watch?v=z9SAzSm24qg
If I was to graph this on a PPC it would look like this