Let the population density of New Mexico be n and that of Texas be t. Then n is measured in the units "people per square mile."
16n + 1 = t. You haven't shared the population density of Texas. Without this info you could write
t-1
16n = t - 1, or n = --------
16
Just supposing that the population density of Tx were 2 people per square mile. Then the population density of New Mexico would be:
2-1
16n = 2 - 1, or n = --------, or n = 1/16 person per square mile (example only).
16
