A contractor has a project to construct a three$-$story office building. The contract drawings show the building is to have a deep foundation consisting of $40$ precast, prestressed concrete piles with an estimated length of $80$ feet. The contractor analyzed the soil report for the project site and determined the soil to be fairly soft. Therefore, she selected a pneumatic $($compressed air$)$ double$-$action hammer to drive the piling. She also selected the other driving equipment and has estimated the daily rental and operating costs shown in Table $1.$ The contractor selected a pile driving crew and estimated the hourly labor costs also shown in Table $1.$

$\backslash$table$[[$Table $1$ Estimated Hourly Cost$],[$Equipment type,$\backslash$table$[[$Hourly Cost $($in US$],[$$$/$hr$)]],$Crane Member,Hourly Cost $($in US$,],[$Crane with boom,$1,450,,\frac{\text{\$}}{?}$ hr$),]]$

The labor costs are per person, so the total labor costs for pile driver workers and laborers are the number of crew members times the hourly rate. Set up time is estimated to be one day, and demobilization time is estimated to be one day. Operational efficiency of the pile driver is estimated to be $30$ minutes per hour, and the driving rate is estimated to be $40$ feet per hour. Transportation costs to bring the equipment to the project site are estimated to be $$4,000,$ and the cost to return the equipment to the rental agency is estimated to be $$4,000.$

a$.$ How many days do you estimate it will take to drive the $40$ piles, if the contractor works eight hours per day?

b$.$ What is the estimated cost to install the piles $($not including the cost of the piles$)?$