(a)D(t) = and S(t)=

At equilibrium =

Squaring both sides and cross multiplying we will have 9t²= 256(25-t)

Or, 9t² +256t -6400=0

9t² + 400t-144t-6400=0

(9t+400) (t-16)=0

Since t cannot acquire any negative value, t= 16 days

(b) at t=16 , D(t) will be or 3 which is the price per book, consumers are prepared to buy

The maximum price which the book can have is when t=0 and is given by D(t)= , that is 5.

Hence the consumer surplus will be 5-3 = 2

(c) at t= 16, S(t)= or 3. It is price at which the Producer is willing to sell

At t=16, the consumers are also willing to buy at D(t)=3. Hence the producer’s surplus is 0

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