A highway construction firm is working on a cut-and-fill stretch of roadway for which dump trucks and power shovels are the primary equipment being used. Time studies reveal the following time values (minutes):
Time to load a truck 10
Travel time to dumping point 15
Dumping time 2
Return time 12
(a) What is the maximum number of trucks that will prevent idle time on the part of the power shovel?
(b) Suppose that it costs $125 per hour to operate the power shovel and $75 per hour to operate each truck. How many trucks should be assigned to the job to minimize the cost per truckload hauled?
(c) Construct a multiple activity chart for the most economical arrangement between dump trucks and the power shovel.