A farmer loaded his truck with 3 boxes of tomatoes, and 5 boxes of cucumbers. Each box of tomatoes weighed 15.5 kilograms, and the total weight of the cucumber boxes was 35 kg more than the total weight of the tomato boxes. If the boxes of cucumbers had identical weights, how many kilograms did 1 box of cucumbers weigh?

Let x be the weight of 1 box of cucumbers.

The total weight of the tomato boxes is 3 * 15.5 = 46.5 kg.
The total weight of the cucumber boxes is 5 * x.

According to the information given, the total weight of the cucumber boxes is 35 kg more than the total weight of the tomato boxes:
5x = 46.5 + 35
5x = 81.5
x = 81.5 / 5
x = 16.3

Therefore, 1 box of cucumbers weighs 16.3 kilograms.