$7\mathrm{.}10$ A grader will be used to maintain $5$ miles of haul road. It is estimated the work will require removing ruts with three passes in first gear, leveling the road with two passes in second gear, and final shaping of the road with three passes in fourth gear. Use an efficiency factor of $80\%.$ Grader speeds are provided in the following chart. Estimate the time requirement for this task.

$\backslash$table$[[$Forward Gears,Maximum Travel Speed $($mph$)],[$First$,2\mathrm{.}5],[$Second$,3\mathrm{.}1],[$Third$,4\mathrm{.}2],[$Fourth$,7\mathrm{.}0]]$