Estimate the social surplus gain obtained when moving from a flat monthly water fee of $250 per household and an average monthly consumption of 100 m³, to a consumption-based price of $1.9/m³, given the following slope estimate from existing studies of comparable municipalities: 

for every $1 increase in the price of water, consumption dropped by 40m³.

(hint: we can go ahead and plot the equation q=Q_max+β_ave×p as representing the demand curve. Note that in order to plot it in the useful format of Figure, we need to represent the equation of the inverse demand curve (price as a function of quantity)