@ half the price and twice the customers you have all the customers who would have bought at the higher price "earning" whatever their surplus would have been + the (half) price - . On top of that you have all of the new customers "earning" a surplus beteen zero and the lower price.
@ half the price and twice the customers you have all the customers who would have bought at the higher price "earning" whatever their surplus would have been + the (half) price - . On top of that you have all of the new customers "earning" a surplus beteen zero and the lower price.