Answer: d.16 days
Explanation:
Hi, using PERT technique we can calculate the mean by applying the next formula:
Mean = (a + 4m + b)/6
Where:
a = optimistic time
m = most likely time
b = pessimistic time
Replacing with the values given:
Mean = (12 +4 (15) + 24)/6
Solving
m = (12+ 60+24)/6
m= 96/6
m = 16 days
Feel free to ask for more if needed or if you did not understand something.