[Music] till now we were talking about the demand schedule and the demand curve of an individual but in order to find the equilibrium in the market and to analyze how markets work we need to work with the demand curve of the entire market so in this lecture I will show you how to convert the individuals demand curves into the market demand curve we know that a market has many consumers of a good we can expect to have millions of consumers who eat ice cream but just for the sake of simplicity let us assume that there are only two consumers who eat ice cream John and Harry and this is how their demand schedule looks like as you can see here call them two shows the quantity demanded by John at different prices and column three shows the quantity demanded by Harry at different prices given this information it is quite simple to obtain the market demand schedule we just need to add the quantity of ice cream cups demanded by John and Harry at different prices so as you can see in column 4 the entire market demands 21 cups of ice cream when the price of ice cream is $0 it decreases to 17 cups of ice cream when the price rises to $1 and so on now that we have got the market demand schedule we can simply graph this to get the market demand curve as you can see I have drawn three demand curves here the first two are for John and Harry respectively and the third demand curve is the market demand curve the market demand curve shows how the total quantity of a good varies as the price of the good varies while all the other factors that affect demand are held constant so this is all about market demand schedule and market demand curve