An initial time study was performed on a process with the following results in minutes $($in minutes$).$ Based on the data obtained so far, assuming an allowance of $20$ percent of the normal time, what do you estimate for the time per customer served, based on this preliminary sample?

$\backslash$table$[[$Element$,\backslash$table$[[$Performance$],[$Rating$]],$Obs $1,0052,0$b$53,$Obs $4,$Obs $5,\backslash$table$[[$Average$],[$Time$]],\backslash$table$[[$Normal$],[$Time$]]],[$Element $1,70,4,3,5,4,3,3\mathrm{.}8,2\mathrm{.}66],[$Element $2,110,8,10,9,11,10,9\mathrm{.}6,10\mathrm{.}56],[$Element $3,90,6,8,7,7,6,6\mathrm{.}8,6\mathrm{.}12]]$