I am editing my question regarding solving the model in order to be more specific.
Regarding the production side, there is only one factor of production which is labor and it is in-elastically supplied, the cost function represents constant marginal costs and overhead cost. l = f +q/$\phi$.I understand that in order to get this pricing rule :
we should get the first order condition of the profit function, however I do not know where does the 1/$\rho$ came from ? (this is my second question)
I apologize if these questions seem silly but I do not have a theoretical background and I am trying to solve the model by myself.
Thanks in advance.