The activity "Ship Container" in your network diagram has an early start of day 17, a late start of day 22 and a late finish of day 37. What is the activity duration?

 

a. 15 days
b. 16. days

c. 59 days

d. 14 days

 

The correct answer is given as "16 days" based on formula LF - LS + 1

I though the correct answer is 15 days based on formula LF - LS