Monohan Machinery specializes in developing weeding equipment used to clean small lakes. George Monohan, the company's president, is convinced that weeding is much better than using chemicals to eradicate weeds. Chemicals pollute and weeds seem to grow faster after you use them. George is thinking of building a machine that will weed narrow rivers and canals. The activities required to build one of these experimental machines are presented in the following table. Build a network for these activities.

12-17 After consulting with Buth Radner, Gorge Monohan was able to determine the activity Times for constructing the weed-harvesting machine to be used on narrow rivers. George would like to determine ES, LS, LF and slack for each activity. The total project completion time and the critical path should also determine (see problem 12-19) for details the activity time are shown in the following table