6) A demand curve for a product is the number of items the consumer will buy at different prices. At a price of $2 a store can sell 2400 of a particular type of toy truck. At a price of $8 the store can sell 600 such trucks. If x represents the price of trucks and y the number of items sold, write an equation for the demand curve.

Given :

When price is $2 dollars he sells 2400 units .

When price is $8 dollars he sells 600 units .

To Find :

If x represents the price of trucks and y the number of items sold, write an equation for the demand curve.

Solution :

Two points are given :

Now , slope is given by :

Now , the equation of line containing these two points and slope -300 is :

Therefore , equation for the demand curve is .

Hence , this is the required solution .