6.84 Four students must work together on a group project.

They decide that each will take responsibility for a particular part of the project, as follows:

Person Maria Alex Juan Jacob Task Survey design Data collection Analysis Report writing Because of the way the tasks have been divided, one student must finish before the next student can begin work.

To ensure that the project is completed on time, a schedule is established, with a deadline for each team member. If any one of the team members is late, the timely completion of the project is jeopardized.

Assume the following probabilities: