For the typical project presented in Table $1,$ the owner of the company asks you the following questions that you need to answer:

Question $1$: What delivery time $($duration$)$ should we promise to the customer if we need to be $90\%$ sure that we will deliver on time?

Question $2$: Winter commences in $15$ days and you prefer that all outdoors activities have finished. What is the probability that roof tiling will be completed by the end of the day $15?$

Question $3$: If the construction manager had promised to the customer the delivery date indicated by the outcome of question $1,$ what would be the probability of delivering late?