Three activities implementable in parallel, have the following time-cost relationships for direct cost component in each:
Activity A:
10 days-800 units; 9 days-900 units;
8 days-1000 units
Activity B:
11 days-1200 units; 10 days-1350 units;
9 days-1500 units
Activity C:
7 days-500 units; 6 days-700 units;
5 days-900 units
The feasible range of total direct cost component for the three activities together is