Ellie’s ECO 105 Archived Resources*

Hi guys and welcome to my resource blog for ECO 105. Below you’ll find archived data from previous ECO 105 classes, but I will also be updating it once a week with current and relevant material!

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About Me

My name is Ellie Moskova and I’ve been an SI Leader for 3 years now (can you believe it?) Sitting through Principles of Microeconomics can be hard the fifth time around but luckily, I love economics. In fact, it’s my major believe it or not! I use economics in my work as a market research intern at a real estate acquisition firm and it’s been great putting principles I’ve learned to real world situations. I’m also the vice-president of my business fraternity. If you need help, have a question, or just want to say hi, you are always welcome to reach out to me via email:


My Session Schedule, Spring 2016


Tuesday 5-6pm, DePaul Center C105

Thursday 10:30-11:30am, DePaul Center C105

Office Hour -Tuesday 10:30-11:30am, DePaul Center C105[/box]

Can’t attend any of my sessions? Check out other ECO 105 SI leaders’ schedules here.

Spring 2016

Week 10


Week 9

Week 8

What is the optimal output if the Price of Q= $6? Calculate it!


Hint: Set MR=MC

Week 7


Week 6



Week 5

Consumer and Producer Surplus





Week 4

Price Ceilings and Price Floors:


Week 3

Individual shifts in demand and supply:

Simultaneous shifts in demand and supply:

Week 2

Download (PDF, 56KB)

Winter 2016

Week 6

Below are the answers to the Midterm Practice Problems I posted. Remember I tried to make these problems as comprehensive as possible and review all the material that is crucial for your understanding. If you do not understand something, I encourage you to email me this weekend.

Download (PDF, 255KB)


Week 5

Week 4


Price controls really do work…if used effectively. Below is a video that examines and explains the impacts of both price floors and price ceilings. If you are confused or just want another lecture, this short video will help clarify!


Week 3

Below is a worksheet I’ve done with my students every quarter. They always find it really helpful. I posted the answers because I want you guys to pay attention to the notation because you can get points off easily!

Download (PDF, 181KB)

Week 2

Countries that produce certain things may decide to trade with other countries. Let’s discuss a few points about trade:

  • A country will only produce what it can produce utilizing all of its available resources. We can see this in a curve called the production possibilities curve.
  • However WITH trade, a country can consume much more than it original could if it was only consuming what it would produce. This curve is called the consumption possibilities curve.
  • Countries only trade if they specialize, or in other words, have a comparative advantage. This means that the opportunity cost for one country is less than the opportunity cost for another. Let’s look at an example:

  • For England to produce 1 Wine, they give up producing 0.83 Cloths.
  • For England to produce 1 Cloth, they give up producing 1.2 Wines.
  • For Portugal to produce 1 Wine, they give up producing 1.125 Cloths.
  • For Portugal to produce 1 Cloth, they give up producing 0.88 Wines.

ENGLAND has the comparative advantage in WINE because they give up less cloths.

PORTUGAL has the comparative advantage in CLOTH because they give up less wines.

Here are some resources from Fall 2015

Midterms are approaching! Don’t let stress and anxiety get in the way of doing well on your exams. The infographic below will give you some tips and tricks to managing your hectic lives.


Price Elasticities:

(The most complicated math you’ll do in ECO 105)

The Price Elasticity of Demand:

 The graph to the left describes the P.E.D, which means how responsive consumers are to a change in price. Make sure you can answer the questions below for the midterm!

  • Why is the P.E.D sign negative?
  • What does it mean if the P.E.D is ><= 1 ?
  • Solve for the P.E.D given a word problem
  • Solve for the P.E.D given a graph
  • Describe what areas of the demand curve represent what kind of elasticities

Shifts in Demand :

I’ve always really liked this picture to illustrate demand shifts because it shows you how income and prices of other goods affect demand.

*Please note that there are two other factors that affect demand: tastes and preferences, and the number of buyers.

Comparative Advantage:

Download (PDF, 181KB)


Supply and Demand Curve:


Demand Curve- The consumer’s willingness to pay for a good. It has an inverse relationship because as price decreases, the quantity demanded increases. As the price increases, the quantity demanded decreases.

Supply Curve- The supplier’s willingness to accept a price for a good. It has a positive relationship because as price increases, quantity supplied will increase. As the price decreases, the quantity supplied decreases.

Equilibrium- The point where the demand curve and supply curve cross. This means that the consumer’s willingness to pay will meet the supplier’s willingness to accept. Notice that there are still suppliers that offer goods at higher prices than people want (no one will buy these goods). And there are suppliers that offer goods at lower prices than people expected to pay (these will be bought up quickly).