Draw the graph · Micro · Supply and demand

Electric cars and gasoline

QuantityPrice0DSE₀
Ddemand
—
Ssupply
—

Drag a curve sideways, or use its arrows. A curve you do not move is a curve you are saying stays put. Make each shift clear enough that a reader could see it.

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Demand shifts left. Supply stays put.

Electric cars are a substitute for gasoline in getting around. When drivers switch, they want less gasoline at every price, so the demand curve shifts left. Nothing happened to refiners' costs or technology, so supply stays put. The lower price then moves sellers down along their supply curve.

Price falls and quantity falls.

Common mistake. A common move is to shift supply left because 'stations sell less gas.' They sell less because buyers want less, and that is a demand shift. The fall in sales is the result, not the cause.

More supply and demand prompts

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Lesson: Shifts in Demand

Every prompt here is one shift. The course chains them: a lesson on why the curve moves, a graded drawing, and spaced review that brings back the shifts you get wrong.