2. Entriken Machinery specializes in developing weed-harvesting equipment that is used to clear small lakes of weeds. Dick Entriken, president of Entriken 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. Dick is contemplating the construction of a machine that could 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 accompanying table. Activity Immediate Time (weeks) predecessor ABCDER A A 6532 B 4 B 5 G C,E 10 H D,F 7 K G,H A 6 a) Develop a PERT network (AOA) for above problem. (5 pts.) b) Determine ES, EF, LS, LF, and slack for each activity. (8 pts.) c) Identify the Critical path and project duration. (7 pts.)