00:01
Okay, in this question we're giving a market described by the following supply and demand functions, where the quantity supplied equals two times the price, and the quantity demanded equals 300 minus the price.
00:13
The first thing that we want to figure out is the equilibrium price and quantity.
00:18
Well, we know that the equilibrium price is such that quantity supplied should equal quantity demanded at that price.
00:27
So, in order to find this price, all we need to do is set quantized applied equal to the qualifying demanded, and we have those two functions here.
00:37
So we'll say 2p equals 300 minus p, and then just adding p to both sides, we'll have 3p equals 300, and we'll find that the equilibrium price is 100.
00:54
From this, we can also plug in the equilibrium price to either the quantity supplied or demanded to arrive at the equilibrium quantity.
01:05
And i'm going to plug it into the demand function this time.
01:09
So i will do 300 minus the equilibrium price of 100, and we will arrive at an equilibrium quantity of 200.
01:17
And of course, you could also multiply 2 by 100 and arrive at the same equilibrium quantity.
01:22
So that's part a.
01:24
For part b, we're going to impose a price ceiling, which i call pmax, of 90.
01:34
Now, recall that the equilibrium price currently is 100.
01:41
We're going to impose a maximum price below equilibrium price, such that you can't engage in market activity above a price of 90.
01:50
And so we can tell by visual inspection alone that this is going to influence equilibrium behavior.
01:56
In particular, we should end up with quantity supplied less than quantity demanded.
02:02
So i'm going to plug in this price 90 to the quantity supplied.
02:10
We'll just have 2 times 90 equals 180.
02:14
And then i will also plug in this price of 90 to the demand function.
02:19
And we'll have 300 minus 90 renders the quantity demanded to be 210.
02:26
So we see the exact behavior that we expect to see.
02:30
And in particular, we know that when quantity supplied is less than quantity demanded, there are more people interested in purchasing the good than that good is available.
02:41
In this case, we have what's known as a shortage...