12-16 Monohan Machinery specializes in developing weed- harvesting equipment that is used to clear small lakes of weeds. George Monohan, president of Monohan Machinery, is convinced that harvesting weeds is far better than using chemicals to kill weeds. Chemicals cause pollution, and the weeds seem to grow faster after chemicals have been used. George is contemplat- ing the construction of a machine that would harvest weeds on narrow rivers and waterways. The activities that are necessary to build one of these experimental weed-harvesting machines are listed in the following table. Construct a network for these activities. ACTIVITIES IMMEDIATE PREDECESSORS A C A D A E B F G C, E D, F H 12-17 After consulting with Butch Radner, George Mono- han was able to determine the activity times for con- structing the weed-harvesting machine to be used on narrow rivers. George would like to determine ES, EF, LS, LF, and slack for each activity. The total project completion time and the critical path should also be determined. (See Problem 12-16 for details.) The activity times are shown in the following table: ACTIVITY TIME (WEEKS) A 6 B 5 C 3 D 2 E 4 F 6 G 10 H 7 12-16 Monohan Machinery specializes in developing weed- harvesting equipment that is used to clear small lakes of weeds. George Monohan, president of Monohan Machinery, is convinced that harvesting weeds is far better than using chemicals to kill weeds. Chemicals cause pollution, and the weeds seem to grow faster after chemicals have been used. George is contemplat- ing the construction of a machine that would harvest weeds on narrow rivers and waterways. The activities that are necessary to build one of these experimental weed-harvesting machines are listed in the following table. Construct a network for these activities. ACTIVITIES IMMEDIATE PREDECESSORS A C A D A E B F G C, E D, F H 12-17 After consulting with Butch Radner, George Mono- han was able to determine the activity times for con- structing the weed-harvesting machine to be used on narrow rivers. George would like to determine ES, EF, LS, LF, and slack for each activity. The total project completion time and the critical path should also be determined. (See Problem 12-16 for details.) The activity times are shown in the following table: ACTIVITY TIME (WEEKS) A 6 B 5 C 3 D 2 E 4 F 6 G 10 H 7