please answer b-d with solution. and explain as well. Silangan Realty has P100 million available for the purchase of new rental property. It has reduced the investment alternatives to townhouses and apartment buildings. Each townhouse can be purchased for P14,100,000, and five are available. Each apartment building can be purchased for P20,000,000, and the developer will construct as many buildings as Silangan wants to purchase. Silangan's property manager can devote up to 140 hours per month to these new properties; each townhouse is expected to require 4 hours per month, and each apartment building is expected to require 40 hours per month. The net annual cash flow is estimated to be P500,000 per townhouse and P750,000 per apartment building. a. Formulate an integer programming model to determine the number of townhouses and the number of apartment buildings that Silangan should purchase to maximize annual cash flow. b. Using Solver, solve the model formulated in part (a) without the integer requirements. What are the optimal solution for the townhouses and the apartment buildings? What is the optimal annual cash flow? c. Round the townhouses and the apartment building values found in part (b). is the solution feasible? Why? d. Truncate the townhouses and the apartment building values found in part (b) (i.e drop the fractional part of each value), Is the solution feasible? Why? e. Add the integer requirements to the model you constructed in part (b) and solve using Solver. What is the optimal number townhouses and apartment buildings and the optimal annual cash flow?