HOW DO I FIND F? NEED HELP WITH F

Ross Hopkins, president of Hopkins Hospitality, has developed the tasks, durations, and predecessor relationships in the following table for building new motels. Time (weeks) Immediate Predecessor(s) Activity a m b A 4 Activity G H 3 3 4 1 1 Time (weeks) a m b 8 12 1 9 24 8 12 16 4 7 9 2 4 6 8 20 B D E F - 5 Immediate Predecessor(s) C, E F F D, G, H I, J A B C, E 1 5 14 J K 5 8 3 4 3 1 4 a) The expected (estimated) time for activity C is 12 weeks. (Round your response to two decimal places.) b) The variance for activity C is 1.77 weeks. (Round your response to two decimal places.) c) Based on the calculation of the estimated times, the critical path is A-B-E-F-H-J-K. d) The estimated time for the critical path is 42.97 weeks. (Round your response to two decimal places.) e) The activity variance along the critical path is 24.94 weeks. (Round your response to two decimal places.) f) Using the standard normal table, the probability that Hopkins Hospitality will finish the project in 40 weeks or less is (Enter as a probability and round your response to three decimal places.)