The total weight of the boxes is 100 boxes x 100 kg/box = 10 000 kg.
The total weight of the crates is 10 crates x 60 kg/crate = <<10*60=600>>600 kg.
The total weight of the sacks is 50 sacks x 50 kg/sack = 2 500 kg.
So, the total weight of the supplies that were already loaded is 10,000 kg+ 600 kg + 2500 kg = <<10000+600+2500=13100>>13,100 kg.
Hence, the most weight that can still be loaded in the truck is 13,500 kg - 13,100 kg = <<13500-13100=400>>400 kg.
This means 400 kg / 40 kg/bag = <<400/40=10>>10 bags can still be loaded in the truck.
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