In order to determine the total number of kilograms from 15 boxes, we need to know the weight of each box in kilograms. Once we know the weight of each box, we can add them together to find the total weight.
If we assume that each box has the same weight of "x" kilograms, then the total weight of 15 boxes can be found by multiplying the weight of one box by the number of boxes:
Total weight = x * 15 kilograms
Without knowing the weight of each box, we cannot determine the total weight in kilograms.