The results of an analysis, on the makeup of garbage, done by the Environmental Protection Agency was published in 1990. Some of the results are given in the following table, which for various years gives the number of pounds per person per day of various types of waste materials.
You can tell that a fraction is a unit fraction when it is over a unit of one. This is also known as unit rate.
N = {15 +- root of ( 225 + 64) } / 2
= {15 +- root of 289 } / 24
= 15 + 17 } / 2 or { 15 -17 } /2
= 16 or -1
There is no answer because there cannot be one to one function inverse.