A company is designing a product layout for a new product. It plans to use this production line eight hours a day in order to meet projected demand of $480$ units per day. The tasks necessary to produce this product are:

Task Time$($secs$)$ Immediate

Predecessor

u $30$ none

v $30$ u

w $6$ u

x $12$ w

y $54$ x

z $30$ v$,$y

If the company wants the output rate to be equal to demand, what would be the efficiency of this line with the theoretical minimum number of workstations?