You have won the tender to construct 21 hen-batteries. It is important to occupy the units as soon as possible. Therefore, the units must be handed over at a rate of about 2 units per week. The company work a 5-day week and a 10-hour day. You want a buffer of 2 days between activities, but fractions of activity times can be absorbed in the buffers, to allow the following activity to start on the start of a new day. All the activities follow on the previous activity, except 4 and 5 that can overlap, as well as 6 and 7 that can overlap. Activity 8 can overlap with 4 and 5 as well as 6 and 7. How long will it take to complete the contract
