Hay Baleer Problem

Problem Statement
This weeks P.O.W. was named, "The Hay Baler Problem", it was about a hay baler who had just finished weighing five bales of hay. Unfortunately, he weighed the bales was in combinations of two. He weighed bale 1 with 2, 1 with 3, 1 with 4, and every other two-baled combination. In the end, he came up with a set of 10 different weights. However, he did not remember which order he weighed the bales and was now supposed to determine the weight of each individual bale, not the bale combinations. Using the final weights (in kilograms) he came up with from all the bale combinations: 80, 82, 83, 84, 85, 86, 87, 88, 90 and 91, it is your job to figure out the final weight of each of the five individual bales of hay. Also, you may want to find out if there is possibly more than one set of weights for this problem, and how you know this.
Process
Schenck for help (He was my old math teacher) because I did not really get it. He didn't understand it either so I gave him the problem so he could think about it over night. I decided to try it again later on over night also. The next day I went to see Mr. Schenck and we first started by trying to solve for the lowest weight 80. We decided we would just try and start adding up two numbers and see if the weights would all work out. We figured that since 80 divided by 2 was 40, and two bales would not weigh the same, we would start with one up from the halfway point 40, and go with 41. This is what we