This graph shows the original supply and demand curves, S0 and D0. You can see the original equilibrium point, E0, at $500 and 15,000 units.
What do you think will be the effect of greater income or an increase in the town's popularity?
The effect of greater income or an increase in the town's popularity is to shift the demand curve to the right, shown on the graph as D1. The new equilibrium point is shown as E1, at $600 and 17,000 units.
Go to the next slide and let's see what happens when we add a price ceiling.