a semi automated assembly mechine had produced 90 parts in a planned running 2 shifts of 8 hrs each.It has capacity of producing 3 parts per minute.The machine experienced breakdown time of 50 min and also it has breaks and sheduled maintenance of 40 min.for changeover and adjustment,total 1 hour and 30 minutes are required.The number of parts rejected and sent for re-works were 12 and 8 respectively.calculate iits overall effectiveness