Two towns had a population of 12,000 in 1990. by 2000, the population of town a had increased by 8 ⁢  % while the population of town b had decreased by 8 ⁢  %. assume these growth and decay rates continued.

For this problem what we should do is write an exponential function for each town.
 We can write the exponential function for decades:
 town a =
 p (t) = 12000 (1.08) ^ (t)
 town b =
 p (t) = 12000 (0.92) ^ (t)
 In both cases:
 t = number of decades.
 We can write the exponential function for years:
 town a =
 p (t) = 12000 (1.08) ^ ((1/10) * t)
 town b =
 p (t) = 12000 (0.92) ^ ((1/10) * t)
 In both cases:
 t = number of years.