Why price
and quantity increase with an increse in demand

4. suppose that pollution in a neighborhood comes from two factories, with marginal benefit curves given by mb1 = 12 – p1 and mb2 = 8 – p2. the level of pollution in the neighborhood is given by p = p1 + p2. the government wants to limit pollution by instituting a pollution-rights market. the government’s desired level of p is 10, so it prints 10 pollution rights and offers them for sale to the firms.a)find the equilibrium selling price of a pollution right, as well as the allocation of rights (and hence pollution levels) across the two factories. b)repeat part (a) for the case where the government’s desired level of pollution equals 14. c)comment on the usefulness of a pollution rights market in achieving efficient levels of pollution abatement.

Acrosswalk_when there are no pavement markings.

Areal estate agent is considering changing her cell phone plan. there are three plans to choose from, all of which involve a monthly service charge of $20. plan a has a cost of $.42 a minute for daytime calls and $.17 a minute for evening calls. plan b has a charge of $.52 a minute for daytime calls and $.15 a minute for evening calls. plan c has a flat rate of $80 with 275 minutes of calls allowed per month and a charge of $.38 per minute beyond that, day or evening.a. determine the total charge under each plan for this case: 150 minutes of day calls and 70 minutes of evening calls in a month. (do not round intermediate calculations. round your answer to 2 decimal places. omit the "$" sign in your response.)c. if the agent will use the service for daytime calls, over what range of call minutes will each plan be optimal? (round each answer to the nearest whole number.include the indifference point itself in each answer.)d. suppose that the agent expects both daytime and evening calls. at what point (i.e., percentage of total call minutes used for daytime calls) would she be indifferent between plans a and b?