Now we consider three tasks A, B and C and these tasks have no particular order.
The required time of each task is T (minutes) and the required number of people is 2.
Now, the simulator can assign 6 people, the task A, B and C can be done in parallel, so total time to complete the task A, B and C is T minutes.
But, the simulator can assign only 2 people at the moment, the task A, B and C should be done in sequence, so total tome to complete is 3T minutes.
So, total time to complete tasks depends on how many people can be assigned in that moment.