Need help on part c. please show how you got the answer.

A project manager has compiled a list of major activities that will be required to install a computer information system in her firm. The list includes estimated completion times for activities and precedence relationships. Use Table B1 and Table B2. Click here for the Excel Data File a. Determine the mean and standard deviation for each of the following paths in the project. (Round Mean and Standard Deviation to 2 decimal places.) b. If the project finishes within 26 weeks of its start, the project manager receives a $1,000 bonus. What is the probability of a $1,000 bonus? (Round z-value to 2 decimal places, and probability to 4 decimal places.) c. If the project finishes within 27 weeks of its start, the project manager receives a $500 bonus. What is the probability of a $500 bonus? (Round z-value to 2 decimal places, and probability to 4 decimal places.)