A drilling operation is required to machine (8)2.0 in. diameter holes on a 20 in. diameter bolt cirile (workpiece thickness is 2 in. A standard twist drill ( V=60SFPM, f= 0.002 ipr) A indexable insert drill ( V=300 sfpm, f= 0.006ipr) The insexable insert toll has a drill point of 0.15 in. If the cost of the machine and operator is $35/hr; the cost of twist drill is $10; the cost of indexable insert drill is $200; HOW many parts must be machined to justify the use of the indexable insert drill?