A mining project is composed of five activities whose three time estimates in months are given below:

Activity	Estimated duration (months)
	Optimistic time	Most likely time	Permissible time
1 - 2	1	1	7
1 - 3	2	5	8
2 - 4	1	1	7
3 - 4	2	5	14
4 - 5	3	6	15

The expected duration of the mining project in months is