30.

(a) For an activity in a PERT network, the following information is available:

Expected time= 9.5 days Optimistic time = 5 days Variance = 6.25 days2 Calculate most likely and pessimistic times of this activity.

(b) The critical activities of a project, their expected durations and standard deviations (in weeks) are given here:

(i) Find the probability that the project will be completed in 45 weeks.
(ii) If the manager wants the probability to be 90 per cent of completing the project in time, how many weeks prior to the deadline should she start the project?

Activity B E Expected duration Standard deviation 22 12 3 2/3 1/3 782 G HT K 7 5 5/3 4/3 0 997 L 6