An initial time study was done on a process with the following results $($in minutes$).$ Based on the data obtained so far, assuming an allowance of $25$ percent of the normal time, what do you estimate for the time per customer served, based on this preliminary sample? $($Round all intermediate calculations to two decimal places.$)$

$\backslash$table$[[$Element$,\backslash$table$[[$Performance$],[$Rating$]],\backslash$table$[[$Obs$],[1]],\backslash$table$[[$Obs$],[2]],\backslash$table$[[$Obs$],[3]],\backslash$table$[[$Obs$],[4]],\backslash$table$[[$Obs$],[5]]],[$Element $1,110,4,6,3,6,3],[$Element $2,70,9,11,9,10,10],[$Element $3,80,6,6,7,7,7]]$

The time per unit customer served is $$ minutes. $($Enter your response rounded to two decimal places.$)$