Around the wind mill a 3867m fence must be built to

protect the installations. 

On the previous project a similar fence has been

built.

It took 6 work days to build a 1200m long fence.

The technical expert brought to your attention the

duration of the task can varies. its pessimistic evaluation of the duration is by far

longer. Due to some local contestations, he would recommend to add 5 more days

to get the pessimistic duration. On the other hand, the estimate duration could

be shorter by one day if the weather is fine and everything goes perfectly

well.

Using the 'Three point estimation' method what is the

estimated duration to build the fence (95% chance to finish on time)