It has been estimated that the world demand for wheat can be represented by thefunction P = 80 - 2Q. It has been further found that the countries supplying thismarket have marginal cost curves which when summed together are given by theequation MC = 5 + Q

What price and output levels will prevail in the world market if a free marketsituation exists?

can any one explain that in detail

The sum of the individual MC curves of producers is the supply curve. That is, MC=5+Q=P. Equilibrium occurs when supply=demand. (so, use algebra, solve for Q)

But why "The sum of the individual MC curves of producers is the supply curve"?In monopoly they are lacking of supply curve??

It has been estimated that the world demand for wheat can be represented by thefunction P = 80 - 2Q. It has been further found that the countries supplying thismarket have marginal cost curves which when summed together are given by theequation MC = 5 + Q

What price and output levels will prevail in the world market if a free marketsituation exists?

why "The sum of the individual MC curves of producers is the supply curve"?In monopoly they are lacking of supply curve??