00:01
So here we have a story.
00:02
And before we do anything about looking at the answers, let's try to actually show what's going on.
00:09
So we know two things here, right? the first thing is that we see at a price of 15, four books are being bought per month.
00:20
So at a price of 15, we observe this point, right? we also observe when the price increases to 20, the book purchases fall to three.
00:32
So we also observe these two points, right? these points are on the demand curve.
00:41
So what has happened here, right? we have not had change in demand.
00:48
A change in demand is when the curve shifts, right? it is a structural change that says for any price, you are interested in less quantity.
00:59
Here, what we have had is a reaction to a changing marketplace, right? there's nothing about the demander that's changed.
01:12
Marta has not changed...