In this case all of the cracks and crevices are sealed. Then a hole is put in the slab to install the small fan and create sub-slab suction. The average Radon mitigation cost in Portland, Oregon, or Vancouver, Washington is between $800 to $2,500 with an average of $1,200.
A central feature of monopolistic competition is that products are differentiated. There are four main types of differentiation: Physical product differentiation, where firms use size, design, colour, shape, performance, and features to make their products different. For example, consumer electronics can easily be physically differentiated.
(In reality they may be the same good one the same demand scale.) An increase in the price of gas at one station will have a perfectly correlated effect on the increase in demand at the other station. Monopolistic competition presents an interesting case of complications with the concept of perfect substitutes.