your house sits on a rectangular lot that has a perimeter of 320 feet. you want to fence the two sides and the back of your lot. your neighbor on the back end wants to have a concrete frence that costs $16 per foot. your side neighbors do not want such an expensive fence and will settle for a fence that is $15 per foot. you received a bid from a local fence company for a total cost of $3134. how much will be your share of the cost assuming your two side neighbors will go in 1/2 (your back neighbor will not help you pay for the fence.)
You don't specify the dimensions of the lot, but we do know that
2(width+length) = 320
length = 160-width
fence costs 2(15w)+16(160-w) = 3134
w = 41
so, the lot is 41x119
119*16 = 1904 for the back fence
82*15 = 1230 for the two side fences
your share 1904 + 1/2 (1230) = 2519