You have 5 bales of hay. for some reason, instead of being weighed individually, they were weighed in all possible...

You have 5 bales of hay. for some reason, instead of being weighed individually, they were weighed in all possible combinations of 2 bales: bales 1 and 2, bales 1 and 3, bales 1 and 4, bales 1 and 5, bales 2 and 3, bales 2 and 4, and so on. the weights of these combinations were writtin down and arranged in numerical order, without keeping track of which weight matched which pair of bales. the weights in kilograms were: 80,82,83,84,85,86,87,88,90, and 91. your task is to find out how much each of the bales weighs. i have the answer but i have no clue how to show my work. could you please help me