An advertising project manager developed the network diagram shown below for a new advertising campagign.  In addition, the manager gathered the time information for each activity, as shown in the below table. 

Estimate the probability that the noncritical path B-F-G will take more than 20 weeks.  Hint:  Subtract from 1.0 the probability that B-F-G will take less than 20 weeks.

Activity                Optimistic           Most likely         Pessimistic         Immediate Predecessor(s)

A                               1                              4                              7                              -

B                                2                              6                              7                              -

C                                3                              3                              6                              B

D                                6                             13                           14                           A

E                               3                              6                              12                           A,C

F                               6                              8                              16                          B

G                               1                              5                              6                           E,F