----------------  SOLUTION  -------------------

solution cost   : 334.964
number of trips : 5

trip 1, 4 customers, sequence : 9 10 15 12 
   weight    : 55
   volume    : 4
   trip cost : 75.7651

trip 2, 2 customers, sequence : 8 7 
   weight    : 42
   volume    : 2
   trip cost : 62.4781

trip 3, 3 customers, sequence : 6 11 5 
   weight    : 55
   volume    : 3
   trip cost : 58.5646

trip 4, 3 customers, sequence : 1 3 2 
   weight    : 53
   volume    : 3
   trip cost : 69.4227

trip 5, 3 customers, sequence : 4 13 14 
   weight    : 53
   volume    : 3
   trip cost : 68.7335