A construction job is comprised of two tasks, which we will call "task A" and "Task B". The two tasks are initiated simultaneously and their completion times are uncertain. The entire construction job is completed as soon as both talks are completed. The possible outcomes for the completion times of task A and task B, and the associated probabilities, are given in the Table.

a) What is the probability distribution of the duration of task A? of task B? of the job as a whole?
b) What are the mean and the standard deviation of the duration of task A? of task B? of the job as a whole?
c) Suppose that task A costs $800 for every week that it is in progress, and that task B costs $1,000 per week for every week that it is in progress, and that there is an additional charge of $400 for every week that the job as a whole is still in progress. Compute the probability distribution, the mean, and the standard deviation of the cost of this construction job.