Coleman Rich Control Devices, Inc., produces custom$-$built relay devices for auto makers. The most recent

project undertaken by Rich requires $14$ different activities. Rich's managers would like to determine the total

project completion time $($in days$)$ and those activities that lie along the critical path. The appropriate data are

shown in the following table:

a$)$ The expected completion time of the project $=53\mathrm{.}67$ days $($round your response to two decimal places$).$

The activities that represent the project's critical path are $A-C-E-H-I-K-M-N.$

b$)$ If the time to complete the activities on the critical path is normally distributed, then the probability that the

critical path will be finished in $53$ days or less $=($round your response to two decimal places$).$