Suppose there are 20 consumers for a good and they have identical demand functions : `d(p) = 10 -3p` for any price less than or equal to `(10)/(3) and d_(1)(p) 0` at any price greater than `(10)/(3)`. What is the market demand funciton ?

Explanation

It can be seen from the given demand functions, that 20 consumer do not want to demand the goods at any price greater than or equal to `(10)/(3)`. All of them demand only at a price of less than Rs `(10)/(3)`.
For a single consumer d[P] = 10 - 3P For 20 consumers,
`d_("market")[P] = [10 xx 3P] xx 20 = 20 - 60 P`, for price `(10)/(3)` and `d_("market")[P] = 0`, ......, for price `gt = (10)/(3)`