How can I answer Part C?

My professor indicated the following:

You are requested to find the threshold value of K so that alternative 4 can yield the cost which is less than the cost you found in problem a,

Problem/solution attached as PDF.

A railroad company has a network sketched below. The freight volumes in an O-D matrix (in tons/day) illustrated below must be transported. A B C A 0 1000 3000 B 5000 0 2500 sh is ar stu ed d vi y re aC s o ou urc rs e eH w er as o. co m From \\ To C 2000 6000 0 B 75 mi C A Let : 100 mi 200 mi F = fixed cost = 5 $/track-mile per hour V = variable cost = 0.02 $/ton-mile Th K = equivalent fixed cost of building a new track = 50 $/track-mile per hour a. What is the present total cost ($/day)? total cost = total fixed cost + total variable cost b. How can the network be modified to minimize total cost? c. Find the threshold value of K to minimize the total cost by constructing a new line linking stations B and C. https://www.coursehero.com/file/12659579/625HW6-online-2015/ Solutions Th sh is ar stu ed d vi y re aC s o ou urc rs e eH w er as o. co m 6-a https://www.coursehero.com/file/12659579/625HW6-online-2015/ sh is ar stu ed d vi y re aC s o ou urc rs e eH w er as o. co m Th https://www.coursehero.com/file/12659579/625HW6-online-2015/ sh is ar stu ed d vi y re aC s o ou urc rs e eH w er as o. co m Th https://www.coursehero.com/file/12659579/625HW6-online-2015/ sh is ar stu ed d vi y re aC s o ou urc rs e eH w er as o. co m Th https://www.coursehero.com/file/12659579/625HW6-online-2015/ sh is ar stu ed d vi y re aC s o ou urc rs e eH w er as o. co m Th https://www.coursehero.com/file/12659579/625HW6-online-2015/ Powered by TCPDF (www.tcpdf.org)