Seven years ago, you started a crosstown delivery service. The service is an environmentally friendly business and, given all the traffic congestion, you are also the fastest service in the city since your entire crew are bicyclists. You have two types of service. You have a small parcel service for anything that is flat and measures less than 11x17. You have a package service using a 100 lb. capacity bike trailer for anything weighing up to 10 lbs. As a way to introduce the new package service when you implemented the small package service, you charged the same price for packages as parcels. You are now wondering if you should charge different prices for the parcel and package service.

Price Parcels and Packages TR MR TC MC MR-MC Profit

100 50 1600

90 120 2300

80 190 3000

70 260 3700

60 330 4400

50 400 5100

40 470 5800

30 540 6500

20 610 7200

10 680 7900

How do I calculate the MR? The feedback my professor gave seems simple but I cannot figure out what I am doing wrong. This is my second attempt on this exam and I need a better grade than I got on my first attempt.