A company must perform a maintenance project consisting of seven activities. The activities, their predecessors, and their respective time estimates are presented here:
Immediate
Activity Designation Predecessor Time in Days
Break down both machines A None 3
Clean machine 1 B A 3
Clean machine 2 C A 3
Re-set machine 1 D B 4
Re-set machine 2 E C 2
Re-calibrate both machines F D and E 1
Final test G F 1
Using CPM, which activities have slack in this project?
a. A, B, C
b. B, D
c. Only C
d. C, E
e. F, G

"jake’s roof repair has provided the following data concerning its costs: fixed cost per month cost per repair-hour wages and salaries $ 20,900 $ 15.00 parts and supplies $ 7.70 equipment depreciation $ 2,800 $ 0.35 truck operating expenses $ 5,720 $ 1.60 rent $ 4,690 administrative expenses $ 3,850 $ 0.50 for example, wages and salaries should be $20,900 plus $15.00 per repair-hour. the company expected to work 2,600 repair-hours in may, but actually worked 2,500 repair-hours. the company expects its sales to be $47.00 per repair-hour. required: compute the company’s activity variances for may."